Alternative phthalocyanine dyes suitable for use in offset inks

ABSTRACT

A phthalocyanine phthalocyanine salt suitable for formulation in a solvent-based or oil-based ink vehicle is disclosed. The phthalocyanine comprises one or more sulfonate groups and a counterion of at least one sulfonate group is an ammonium cation comprising at least 15 carbon atoms. Ammonium salts of sulfonated gallium naphthalocyanines exemplify such phthalocyanine salts.

FIELD OF THE INVENTION

The present application relates to phthalocyanine salts, such asnaphthalocyanines. It has been developed primarily for optimizing theabsorption characteristics of IR-absorbing phthalocyanine dyes orpigments in oil-based inks suitable for analog printing.

CROSS REFERENCE TO OTHER RELATED APPLICATIONS

The following patents or patent applications filed by the applicant orassignee of the present invention are hereby incorporated bycross-reference.

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BACKGROUND OF THE INVENTION

IR absorbing dyes have numerous applications, such as optical recordingsystems, thermal writing displays, laser filters, infrared photography,medical applications and printing. Typically, it is desirable for thedyes used in these applications to have strong absorption in the near-IRat the emission wavelengths of semiconductor lasers (e.g. between about700 and 2000 nm, preferably between about 700 and 1000 nm). In opticalrecording technology, for example, gallium aluminium arsenide (GaAlAs)and indium phosphide (InP) diode lasers are widely used as lightsources.

Another important application of IR dyes is in inks, such as printinginks. The storage and retrieval of digital information in printed formis particularly important. A familiar example of this technology is theuse of printed, scannable bar codes. Bar codes are typically printedonto tags or labels associated with a particular product and containinformation about the product, such as its identity, price etc. Barcodes are usually printed in lines of visible black ink, and detectedusing visible light from a scanner. The scanner typically comprises anLED or laser (e.g. a HeNe laser, which emits light at 633 nm) lightsource and a photocell for detecting reflected light. Black dyessuitable for use in barcode inks are described in, for example,WO03/074613.

However, in other applications of this technology (e.g. securitytagging) it is desirable to have a barcode, or other intelligiblemarking, printed with an ink that is invisible to the unaided eye, butwhich can be detected under UV or IR light.

An especially important application of detectable invisible ink is inautomatic identification systems, and especially “netpage” and“Hyperlabel™” systems. Netpage systems are described in the patents andpatent applications listed in the cross reference section.

The disclosures of all of these co-pending patents/patent applicationsare incorporated herein by reference. Some patent applications aretemporarily identified by their docket number. These will be replaced bythe corresponding application number when available.

In general, the netpage system relies on the production of, and humaninteraction with, netpages. These are pages of text, graphics and imagesprinted on ordinary paper, but which work like interactive web pages.Information is encoded on each page using ink which is substantiallyinvisible to the unaided human eye. The ink, however, and thereby thecoded data, can be sensed by an optically imaging pen and transmitted tothe netpage system.

Active buttons and hyperlinks on each page may be clicked with the pento request information from the network or to signal preferences to anetwork server. In some forms, text written by hand on a netpage may beautomatically recognized and converted to computer text in the netpagesystem, allowing forms to be filled in. In other forms, signaturesrecorded on a netpage may be automatically verified, allowing e-commercetransactions to be securely authorized.

Netpages are the foundation on which a netpage network is built. Theymay provide a paper-based user interface to published information andinteractive services.

A netpage consists of a printed page (or other surface region) invisiblytagged with references to an online description of the page. The onlinepage description is maintained persistently by a netpage page server.The page description describes the visible layout and content of thepage, including text, graphics and images. It also describes the inputelements on the page, including buttons, hyperlinks, and input fields. Anetpage allows markings made with a netpage pen on its surface to besimultaneously captured and processed by the netpage system.

Multiple netpages can share the same page description. However, to allowinput through otherwise identical pages to be distinguished, eachnetpage is assigned a unique page identifier. This page ID hassufficient precision to distinguish between a very large number ofnetpages.

In a preferred form suitable for use with the Applicant's digital inkjetprinters, each reference to the page description is encoded in a printedtag. The tag identifies the unique page on which it appears, and therebyindirectly identifies the page description. The tag also identifies itsown position on the page.

Tags are printed in infrared-absorptive ink on any substrate which isinfrared-reflective, such as ordinary paper. Near-infrared wavelengthsare invisible to the human eye but are easily sensed by a solid-stateimage sensor with an appropriate filter.

A tag is sensed by an area image sensor in the netpage pen, and the tagdata is transmitted to the netpage system via the nearest netpageprinter. The pen is wireless and communicates with the netpage printervia a short-range radio link. Tags are sufficiently small and denselyarranged that the pen can reliably image at least one tag even on asingle click on the page. It is important that the pen recognize thepage ID and position on every interaction with the page, since theinteraction is stateless. Tags are error-correctably encoded to makethem partially tolerant to surface damage.

The netpage page server maintains a unique page instance for eachprinted netpage, allowing it to maintain a distinct set of user-suppliedvalues for input fields in the page description for each printednetpage.

Hyperlabel™ is a trade mark of Silverbrook Research Pty Ltd, Australia.In a preferred form of Hyperlabel™ which is suitable for use with theApplicant's digital inkjet printers, an invisible (e.g. infrared)tagging scheme uniquely identifies a product item. This has thesignificant advantage that it allows the entire surface of a product tobe tagged, or a significant portion thereof, without impinging on thegraphic design of the product's packaging or labeling. If the entiresurface of a product is tagged (“omnitagged”), then the orientation ofthe product does not affect its ability to be scanned i.e. a significantpart of the line-of-sight disadvantage of visible barcodes iseliminated. Furthermore, if the tags are compact and massivelyreplicated (“omnitags”), then label damage no longer prevents scanning.

Thus, Hyperlabel tagging consists of covering a large portion of thesurface of a product with optically-readable invisible tags. When thetags utilize reflection or absorption in the infrared spectrum, they arereferred to as infrared identification (IRID) tags. Each Hyperlabel™ tagmay uniquely identify the product on which it appears. Each tag alsooptionally identifies its own position on the surface of the productitem, to provide the downstream consumer benefits of netpageinteractivity.

Hyperlabels™ are typically applied during product manufacture and/orpackaging using digital printers, preferably inkjet printers. These maybe add-on infrared printers, which print the tags after the text andgraphics have been printed by other means, or integrated colour andinfrared printers which print the tags, text and graphicssimultaneously.

Hyperlabels™ can be detected using similar technology to barcodes,except using a light source having an appropriate near-IR frequency. Thelight source may be a laser (e.g. a GaAlAs laser, which emits light at830 nm) or it may be an LED.

In our copending U.S. application Ser. Nos. 11/488,162 and 11/488,163filed on Jul. 18, 2006, the contents of which are incorporated herein bycross-reference, we described an alternative to printing Hyperlabel™tags using a digital printer. In this alternative system, tags areprinted by an analog (e.g. offset) printing process and the product itemcarries an independent identifier and/or a layout identifier encodedinto the tags. This alternative system has the advantage that the tagsare not required to uniquely identify each individual product item andcan therefore be printed by an analog printing process, which printsmultiple batches of identical tags onto a media web.

It would therefore be desirable to provide an IR-absorbing dye, suitablefor formulation into an analog printing ink. Typically, offset printinginks are oil-based inks.

It would be further desirable for the dye to exhibit propertiescompatible with netpage and Hyperlabel™ systems, such as intenseabsorption in the near infra-red region (e.g. 700 to 1000 nm); zero orlow intensity visible absorption; good lightfastness; good thermalstability; zero or low toxicity; and low-cost manufacture.

Some IR dyes are commercially available from various sources, such asEpolin Products, Fujifilm Imaging Colorants and H.W. Sands Corp.

In addition, the prior art describes various IR dyes. U.S. Pat. No.5,460,646, for example, describes an infrared printing ink comprising acolorant, a vehicle and a solvent, wherein the dye is a silicon (IV)2,3-naphthalocyanine bis-trialkylsilyloxide.

U.S. Pat. No. 5,282,894 describes a solvent-based printing inkcomprising a metal-free phthalocyanine, a complexed phthalocyanine, ametal-free naphthalocyanine, a complexed naphthalocyanine, a nickeldithiolene, an aminium compound, a methine compound or an azulenesquaricacid.

However, prior art oil-based inks tend to be highly colored andunsuitable for netpage and Hyperlabel™ applications.

SUMMARY OF THE INVENTION

In a first aspect, there is provided a phthalocyanine salt comprisingone or more sulfonate groups, wherein a counterion of at least onesulfonate group is an ammonium cation comprising at least 15 carbonatoms. Typically, the phthalocyanine salt is suitable for formulation ina solvent-based or oil-based ink vehicle. The phthalocyanine salt may bea dye or pigment, depending on its specific solubility characteristicsin a particular ink vehicle.

Optionally, the counterion of the at least one sulfonate group is anammonium cation comprising at least 16 carbon atoms, at least 17 carbonatoms, at least 18 carbon atoms, at least 19 carbon atoms or at least 20carbon atoms.

Optionally, the ammonium cation comprises at least one group C₆₋₃₀ alkylgroup or at least one C₆₋₃₀ benzylalkyl group. Typically, the ammoniumcation comprises at least one group C₆₋₁₈ alkyl group or at least oneC₆₋₁₈ benzylalkyl group. Typically, the ammonium cation comprises atleast one group C₆₋₁₆ alkyl group or at least one C₆₋₁₆ benzylalkylgroup.

Optionally, the phthalocyanine salt comprises a plurality of sulfonategroups.

Optionally, the phthalocyanine salt comprises a corresponding pluralityof ammonium cations.

Optionally, the phthalocyanine salt is an IR-absorbing dye or pigment,which may be a naphthalocyanine.

Optionally, the or each ammonium cation comprises at least 17 or,optionally, at least 20 carbon atoms.

Optionally, the ammonium cation is of formula:N⁺(R^(m))(R^(n))(R^(s))(R^(t)), wherein:

-   -   each of R^(m), R^(n), R^(s) and R^(t) is independently selected        from C₁₋₃₀ alkyl, C₅₋₁₂ aryl and C₅₋₃₀ arylalkyl; or    -   R^(m) and R^(n) are together joined to form a C₅₋₁₀        heterocycloalkyl group, with R^(s) and R^(t) being independently        selected from C₁₋₃₀ alkyl, C₅₋₁₂ aryl and C₅₋₃₀ arylalkyl; or    -   R^(m), R^(n) and R^(s) are together joined to form a C₅₋₁₀        heteroaryl group, with R^(t) being independently selected from        C₁₋₃₀ alkyl, C₅₋₁₂ aryl and C₅₋₃₀ arylalkyl.

Optionally, at least one of R^(m), R^(n), R^(s) and R^(t) comprises 10or more carbon atoms.

Optionally, at least two of R^(m), R^(n), R^(s) and R^(t) comprise 6 ormore carbon atoms.

Optionally, at least three of R^(m), R^(n), R^(s) and R^(t) comprise 6or more carbon atoms.

Optionally, each of R^(m), R^(n), R^(s) and R^(t) is independentlyselected from C₁₋₃₀ alkyl.

Optionally, the ammonium cation is of formula:

Optionally, the phthalocyanine salt is of formula (I):

wherein

-   M is Ga(A¹);-   A¹ is an axial ligand selected from —OH, halogen, —OR³, —OC(O)R⁴ or    —O(CH₂CH₂O)_(e)R^(e) wherein e is an integer from 2 to 10 and R^(e)    is H, C₁₋₈ alkyl or C(O)C₁₋₈ alkyl;-   R³ is selected from C₁₋₂₀ alkyl, C₅₋₁₂ aryl, C₅₋₂₀ arylalkyl or    Si(R^(x))(R^(y))(R^(z));-   R⁴ is selected from C₁₋₂₀ alkyl, C₅₋₂₀ aryl or C₅₋₁₂ arylalkyl;-   R^(x), R^(y) and R^(z) may be the same or different and are selected    from C₁₋₁₂ alkyl, C₅₋₁₂ aryl, C₅₋₁₂ arylalkyl, C₁₋₁₂ alkoxy, C₅₋₁₂    aryloxy or C₅₋₁₂ arylalkoxy; and-   Z₁ ⁺, Z₂ ⁺, Z₃ ⁺ and Z₄ ⁺ may be the same or different and are each    an ammonium cation comprising at least 15 carbon atoms.

In a second aspect, there is provided a solvent-based or oil-based inkcomprising a phthalocyanine salt as described above.

In a third aspect, there is provided an analog printer, or a modulethereof, comprising an ink supply, a printing plate and means fordisposing ink from the ink supply onto the plate, wherein the inkcomprises a phthalocyanine salt as described above.

In a fourth aspect, there is provided a substrate having aphthalocyanine salt as described above disposed thereon or therein.Optionally, the substrate is a label, packaging or surface of a productitem.

In a fifth aspect, there is provided a system for interacting with acoded substrate, the system comprising:

-   -   a substrate having human-readable information and        machine-readable coded data disposed thereon or therein; and    -   a sensing device for reading the machine-readable coded data,        wherein the coded data comprises a phthalocyanine salt as        described above.

In a sixth aspect, there is provided a method of initiating a requestedaction in a computer system via a printed substrate, the substratecontaining human-readable information and machine-readable coded data,the method including the steps of:

positioning a sensing device in an operative position relative to thesubstrate;

sensing at least some of the coded data;

generating indicating data in the sensing device using at least some ofthe sensed coded data, said indicating data enabling the computer toidentify the requested action; and

sending the indicating data to the computer system,

wherein said coded data comprises a phthalocyanine salt as describedabove.

In a seventh aspect, there is provided a method of interacting with aproduct item, the product item having a printed surface containinghuman-readable information and machine-readable coded data, the methodincluding the steps of:

positioning a sensing device in an operative position relative to thesurface;

sensing at least some of the coded data;

generating indicating data in the sensing device using at least some ofthe sensed coded data, said indicating data enabling the computer toidentify a parameter relating to the interaction; and

sending the indicating data to the computer system,

wherein said coded data comprises a phthalocyanine salt as describedabove.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic of a the relationship between a sample printednetpage and its online page description;

FIG. 2 is a schematic view of a interaction between a netpage pen, a Webterminal, a netpage printer, a netpage relay, a netpage page server, anda netpage application server, and a Web server;

FIG. 3 illustrates a collection of netpage servers, Web terminals,printers and relays interconnected via a network;

FIG. 4 is a schematic view of a high-level structure of a printednetpage and its online page description;

FIG. 5A is a plan view showing the interleaving and rotation of thesymbols of four codewords of the tag;

FIG. 5B is a plan view showing a macrodot layout for the tag shown inFIG. 5 a;

FIG. 5C is a plan view showing an arrangement of nine of the tags shownin FIGS. 5 a and 5 b, in which targets are shared between adjacent tags;

FIG. 5D is a plan view showing a relationship between a set of the tagsshown in FIG. 5 a and a field of view of a netpage sensing device in theform of a netpage pen;

FIG. 6 is a perspective view of a netpage pen and its associatedtag-sensing field-of-view cone;

FIG. 7 is a perspective exploded view of the netpage pen shown in FIG.6;

FIG. 8 is a schematic block diagram of a pen controller for the netpagepen shown in FIGS. 6 and 7;

FIG. 9 is a perspective view of a wall-mounted netpage printer;

FIG. 10 is a section through the length of the netpage printer of FIG.9;

FIG. 10A is an enlarged portion of FIG. 10 showing a section of theduplexed print engines and glue wheel assembly;

FIG. 11 is a detailed view of the ink cartridge, ink, air and gluepaths, and print engines of the netpage printer of FIGS. 9 and 10;

FIG. 12 is an exploded view of an ink cartridge;

FIG. 13 is a schematic view of the structure of an item ID;

FIG. 14 is a schematic view of the structure of a Hyperlabel tag;

FIG. 15 is a schematic view of a pen class diagram;

FIG. 16 is a schematic view of the interaction between a product item, afixed product scanner, a hand-held product scanner, a scanner relay, aproduct server, and a product application server;

FIGS. 17(A) to 17(C) show the basic operational principles of a thermalbend actuator;

FIG. 18 shows a three dimensional view of a single ink jet nozzlearrangement constructed in accordance with FIG. 17;

FIG. 19 shows an array of the nozzle arrangements shown in FIG. 18;

FIG. 20 is an example of a layout ID class diagram;

FIG. 21 is an alternative example of Hyperlabel tag class diagram;

FIG. 22 shows a product item having Hyperlabel tags and a separate RFIDtag;

FIG. 23 shows a product item having Hyperlabel tags and a separatebarcode identifier;

FIG. 24 shows a product item having Hyperlabel tags overprinted with anink containing a randomly dispersed taggant;

FIG. 25 shows a reflectance spectrum of a printed swatch of Aliquat® 336salt 5 at 1% w/w dye loading;

FIG. 26 shows a reflectance spectrum of a printed swatch of the Aliquat®336 salt 5 at 2% w/w dye loading;

FIG. 27 shows a reflectance spectrum of a printed swatch of the Aliquat®336 salt 5 at 3% w/w dye loading;

FIG. 28 shows the relationship between Aliquat® 336 salt 5 loading andabsorption at 800-810 nm;

FIG. 29 shows a ¹H NMR (d₆-DMSO) spectrum of the Aliquat® 336 salt 5;

FIG. 30 shows a reflectance spectrum of an offset printed strip ofhexadecyloxygallium naphthalocyanine 10 at 3% w/w;

FIG. 31 shows a reflectance spectrum of thetetrakis(didodecyldimethylammonium) salt 6 on photographic paper;

FIG. 32 shows a reflectance spectrum of the tetra(N-hexadecylpyridinium)salt 7 on photographic paper;

FIG. 33 shows a reflectance spectrum of thetetra(hexadecyltrimethylammonium) salt 8 on photographic paper;

FIG. 34 shows a reflectance spectrum of the tetrakis(tetraoctylammonium)salt 11 on photographic paper;

FIG. 35 shows a reflectance spectrum of thetetrakis(tetraoctadecylammonium) salt 12 on photographic paper;

FIG. 36 shows a reflectance spectrum of the tetra(benzethonium) salt 15on photographic paper;

FIG. 37 shows a reflectance spectrum of thetetrakis(trioctadecylmethylammonium) salt 18 on photographic paper;

FIG. 38 shows a reflectance spectrum of the tetrakis(tetrahexylammonium)salt 19 on photographic paper;

FIG. 39 shows a reflectance spectrum of the tetrakis(trioctylamine) salt20 on photographic paper; and

FIG. 40 shows a reflectance spectrum of the tetrakis(tridodecylamine)salt 21 on photographic paper.

DETAILED DESCRIPTION

IR-Absorbing Dye

As used herein, the term “phthalocyanine” refers to any compoundbelonging to the general class of macrocyclic phthalocyanines, andincludes naphthalocyanines, quinolinephthalocyanines etc, as well assubstituted derivatives thereof.

As used herein, the term “IR-absorbing dye” or “IR-absorbing pigment”means a substance, which absorbs infrared radiation and which istherefore suitable for detection by an infrared sensor. Preferably, theIR-absorbing dye or pigment absorbs in the near infrared region, andpreferably has a λ_(max) in the range of 700 to 1000 nm, more preferably750 to 900 nm, more preferably 780 to 850 nm. Dyes having a λ_(max) inthis range are particularly suitable for detection by semiconductorlasers, such as a gallium aluminium arsenide diode laser.

Formulations according to the present invention have the advantageousfeatures of: low cost, low visibility and suitability for formulationinto solvent-based or oil-based inks. Accordingly, the dyes of thepresent invention may be suitable for use in netpage and Hyperlabel™applications, where coded data is printed by an analog (e.g. offset)printing process, as described in our copending U.S. application Ser.Nos. 11/488,162 and 11/488,163 filed on Jul. 18, 2006, the contents ofwhich are incorporated herein by reference.

Hitherto, ammonium salts of sulfonated phthalocyanines had not beenproposed as IR-absorbing dyes suitable for formulation intosolvent-based or oil-based inks. Traditionally, the inherenthydrophobicity of the phthalocyanine macrocycle had been exploited as ameans for solubilizing phthalocyanines into solvents or oils. However,in the present invention, the phthalocyanine is sulfonated and thecounterion provides the hydrophobicity necessary for solubilization inoils. One advantage of this approach is that complementary water-solubleand oil-soluble dyes may be manufactured from a common sulfonic acidintermediate.

A further advantage is that the complementary water-soluble andoil-soluble dyes (or pigments) have the same chromophore and thereforehave similar λ_(max). IR dyes are usually designed for use with aspecific IR sensor which has maximum sensitivity to a particularwavelength. It is therefore desirable to produce a suite ofcomplementary aqueous-based and oil-based dyes, printable by digital(e.g. inkjet) or analog (e.g. offset) processes, which have the sameλ_(max) and optimized for use with the same IR sensor. It will bereadily appreciated that the oil- and solvent-soluble dyes describedbelow in the Examples below are complementary with the water-solubledyes described in, for example our earlier U.S. Pat. No. 7,148,435, thecontents of which is incorporated herein by reference. The dyes eachshare the same sulfonated gallium naphthalocyanine chromophore andtherefore have similar absorption characteristics.

In our earlier U.S. patent application No. 60/851,754, filed on Oct. 16,2006, the contents of which is incorporated herein by reference, wedescribed how phosphonium salts were suitable for formulatingphthalocyanine dyes into solvent-based or oil-based ink vehicles.However, it has now been found that certain ammonium salts also enablesulfonated phthalocyanines to be formulated into non-aqueous inkvehicles, which are typically used for offset printing. In particular,it has been found that ammonium salts comprising at least 15 carbonatoms are suitable for this purpose.

Aliquat® 336 is an example of a commercially available ammonium salt,which is suitable for use in the present invention. Aliquat® 336 is amixture of predominantly methyltrioctylammonium chloride withtricaprylmethylammonium chloride. It is relatively inexpensive andreadily available, making it an excellent alternative to the phosphoniumsalts described previously by the present Applicant.

A further advantage of IR dyes according to the present invention istheir low visibility. The low visibility is believed to be a result ofreduced π-π stacking between adjacent molecules. The bulky ammoniumcation comprising at least 15 carbon atoms is believed to interruptaggregation, thereby providing a greater monomer component with asharper Q-band. A sharper Q-band in the IR region generally providesless absorption in the visible region, and therefore lower overallvisibility when printed.

Notwithstanding the significant cost improvement of the present ammoniumsalts compared with the phosphonium salts described in U.S. ApplicationNo. 60/851,754 filed on Oct. 16, 2006, the ammonium salts also exhibitsurprisingly high stability when printed. This unexpected higherstability of ammonium salts, as compared to their phosphoniumcounterparts, makes the ammonium salts particularly attractive for usein offset inks.

In the most general form of the present invention, the phthalocyaninedye may be metal-free or may comprise a central metal atom moiety M.Optionally, M is selected from Si(A¹)(A²), Ge(A¹)(A²), Ga(A¹), Mg,Al(A¹), TiO, Ti(A¹)(A²), ZrO, Zr(A¹)(A²), VO, V(A¹)(A²), Mn, Mn(A²), Fe,Fe(A¹), Co, Ni, Cu, Zn, Sn, Sn(A¹)(A²), Pb, Pb(A¹)(A²), Pd and Pt.Phthalocyanines having a range of central metal atom moieties are wellknown in the literature (see, for example, Aldrich Catalogue).

Optionally, M is selected from Si(A¹)(A²), Ge(A¹)(A²), Ga(A¹), Al(A¹),VO, Mn, Mn(A¹), Cu, Zn, Sn, and Sn(A¹)(A²).

Optionally, M is Ga(A¹).

A¹ and A² are axial ligands, which may be the same or different.Optionally, A¹ and A² and are selected from —OH, halogen or —OR³.Optionally, A¹ and A² may be —OC(O)R⁴ or —O(CH₂CH₂O)_(e)R^(e) wherein eis an integer from 2 to 10 and R^(e) is H, C₁₋₈ alkyl or C(O)C₁₋₈ alkyl.

R³ may be C₁₋₂₀ alkyl, C₅₋₁₂ aryl, C₅₋₂₀ arylalkyl orSi(R^(x))(R^(y))(R^(z)).

R⁴ may be C₁₋₂₀ alkyl, C₅₋₁₂ aryl or C₅₋₂₀ arylalkyl.

R^(x), R^(y) and R^(z) may be the same or different and are selectedfrom C₁₋₁₂ alkyl, C₅₋₁₂ aryl, C₅₋₁₂ arylalkyl, C₁₋₁₂ alkoxy, C₅₋₁₂aryloxy or C₅₋₁₂ arylalkoxy.

Typically A¹ is a hydroxyl group (—OH). Alternatively, A¹ may beselected or modified to impart specific properties onto the dyemolecule. A¹ may be selected to add axial steric bulk to the dyemolecule, thereby further reducing cofacial interactions betweenadjacent dye molecules.

Optionally, the salt is of formula (Ia):

wherein:

-   Q¹, Q², Q³ and Q⁴ are the same or different and are independently    selected from a C₃₋₂₀ arylene group or a C₃₋₂₀ heteroarylene group;-   M is (H₂) or a metal selected from the group comprising: Si(A¹)(A²),    Ge(A¹)(A²), Ga(A¹), Mg, Al(A¹), TiO, Ti(A¹)(A²), ZrO, Zr(A¹)(A²),    VO, V(A¹)(A²), Mn, Mn(A¹), Fe, Fe(A¹), Co, Ni, Cu, Zn, Sn,    Sn(A¹)(A²), Pb, Pb(A¹)(A²), Pd and Pt;-   A¹ and A² are axial ligands, which may be the same or different, and    are selected from the group comprising: —OH, halogen, —OR³, —OC(O)R⁴    and —O(CH₂CH₂O)_(e)R^(e) wherein e is an integer from 2 to 10 and    R^(e) is H, C₁₋₈ alkyl or C(O)C₁₋₈ alkyl;-   R³ is C₁₋₂₀ alkyl, C₅₋₁₂ aryl, C₅₋₂₀ arylalkyl or    Si(R^(x))(R^(y))(R^(z));-   R⁴ is C₁₋₂₀ alkyl, C₅₋₁₂ aryl or C₅₋₂₀ arylalkyl;-   R^(x), R^(y) and R^(z) are the same or different and are selected    from C₁₋₁₂ alkyl, C₅₋₁₂ aryl, C₅₋₁₂ arylalkyl, C₁₋₁₂ alkoxy, C₅₋₁₂    aryloxy or C₅₋₁₂ arylalkoxy; and-   Z₁ ⁺, Z₂ ⁺, Z₃ ⁺ and Z₄ ⁺ may be the same or different and are each    an ammonium cation comprising at least 15 carbon atoms.

Optionally, Q¹, Q², Q³ and Q⁴ are such that compound (Ia) is aphthalocyanine or a naphthalocyanine salt.

Optionally, the salt is of formula (II):

wherein

-   M is (H₂) or a metal selected from the group comprising: Si(A¹)(A²),    Ge(A¹)(A²), Ga(A¹), Mg, Al(A¹), TiO, Ti(A¹)(A²), ZrO, Zr(A¹)(A²),    VO, V(A¹)(A²), Mn, Mn(A¹), Fe, Fe(A¹), Co, Ni, Cu, Zn, Sn,    Sn(A¹)(A²), Pb, Pb(A¹)(A²), Pd and Pt;-   A¹ is an axial ligand selected from —OH, halogen, —OR³, —OC(O)R⁴ or    O(CH₂CH₂O)_(e)R^(e) wherein e is an integer from 2 to 10 and R^(e)    is H, C₁₋₈ alkyl or C(O)C₁₋₈ alkyl;-   R³ is selected from C₁₋₁₂ alkyl, C₅₋₁₂ aryl, C₅₋₁₂ arylalkyl or    Si(R^(x))(R^(y))(R^(z));-   R⁴ is selected from C₁₋₁₂ alkyl, C₅₋₁₂ aryl or C₅₋₁₂ arylalkyl;-   R^(x), R^(y) and R^(z) may be the same or different and are selected    from C₁₋₁₂ alkyl, C₅₋₁₂ aryl, C₅₋₁₂ arylalkyl, C₁₋₁₂ alkoxy, C₅₋₁₂    aryloxy or C₅₋₁₂ arylalkoxy; and-   Z₁ ⁺, Z₂ ⁺, Z₃ ⁺ and Z₄ ⁺ may be the same or different and are each    an ammonium cation comprising at least 15 carbon atoms.

An example of a phthalocyanine salt according to the present inventionis shown in formula (I):

wherein

-   M is Ga(A¹);-   A¹ is an axial ligand selected from —OH, halogen, —OR³, —OC(O)R⁴ or    —O(CH₂CH₂O)_(e)R^(e) wherein e is an integer from 2 to 10 and R^(e)    is H, C₁₋₈ alkyl or C(O)C₁₋₈ alkyl;-   R³ is selected from C₁₋₁₂ alkyl, C₅₋₁₂ aryl, C₅₋₁₂ arylalkyl or    Si(R^(x))(R^(y))(R^(z));-   R⁴ is selected from C₁₋₁₂ alkyl, C₅₋₁₂ aryl or C₅₋₁₂ arylalkyl;-   R^(x), R^(y) and R^(z) may be the same or different and are selected    from C₁₋₁₂ alkyl, C₅₋₁₂ aryl, C₅₋₁₂ arylalkyl, C₁₋₁₂ alkoxy, C₅₋₁₂    aryloxy or C₅₋₁₂ arylalkoxy; and-   Z₁ ⁺, Z₂ ⁺, Z₃ ⁺ and Z₄ ⁺ may be the same or different and are each    an ammonium cation comprising at least 15 carbon atoms.

Optionally, M is Ga(OH).

Optionally, each Z₁ ⁺, Z₂ ⁺, Z₃ ⁺ and Z₄ ⁺ is of formula:N⁺(R^(m))(R^(n))(R^(s))(R^(t)), wherein:

-   -   each of R^(m), R^(n), R^(s) and R^(t) is independently selected        from C₁₋₃₀ alkyl, C₅₋₁₂ aryl and C₅₋₃₀ arylalkyl; or    -   R^(m) and R^(n) are together joined to form a C₅₋₁₀        heterocycloalkyl group, with R^(s) and R^(t) being independently        selected from C₁₋₃₀ alkyl, C₅₋₁₂ aryl and C₅₋₃₀ arylalkyl; or    -   R^(m), R^(n) and R^(s) are together joined to form a C₅₋₁₀        heteroaryl group, with R^(t) being independently selected from        C₁₋₃₀ alkyl, C₅₋₁₂ aryl and C₅₋₃₀ arylalkyl.

The present Applicant has described previously the use of galliumnaphthalocyanines as IR dyes. These compounds are readily synthesized,have strong absorption in the near-IR region and have surprisingly lowabsorption in the visible region. Dyes according to formula (I)facilitate the use of gallium naphthalocyanines in non-aqueous inkvehicles.

The term “aryl” is used herein to refer to an aromatic group, such asphenyl, naphthyl or triptycenyl. C₆₋₁₂ aryl, for example, refers to anaromatic group having from 6 to 12 carbon atoms, excluding anysubstituents. The term “arylene”, of course, refers to divalent groupscorresponding to the monovalent aryl groups described above. Anyreference to aryl implicitly includes arylene, where appropriate.

The term “heteroaryl” refers to an aryl group, where 1, 2, 3 or 4 carbonatoms are replaced by a heteroatom selected from N, O or S. Examples ofheteroaryl (or heteroaromatic) groups include pyridyl, benzimidazolyl,indazolyl, quinolinyl, isoquinolinyl, indolinyl, isoindolinyl, indolyl,isoindolyl, pyrrolyl, imidazolyl, oxazolyl, isoxazolyl, pyrazolyl,isoxazolonyl, piperazinyl, pyrimidinyl, pyridyl, pyrimidinyl,benzopyrimidinyl, benzotriazole, quinoxalinyl, pyridazyl etc.

Unless specifically stated otherwise, aryl and heteroaryl groups may beoptionally substituted with 1, 2, 3, 4 or 5 of the substituentsdescribed below. The optional substituent(s) are independently selectedfrom C₁₋₈ alkyl, C₁₋₈ alkoxy, —(OCH₂CH₂)_(d)OR^(d) (wherein d is aninteger from 2 to 5000 and R^(d) is H, C₁₋₈ alkyl or C(O)C₁₋₈ alkyl),cyano, halogen, amino, hydroxyl, thiol, —SR^(v), —NR^(u)R^(v), nitro,phenyl, phenoxy, —CO₂R^(v), —C(O)R^(v), —OCOR^(v), —SO₂R^(v),—OSO₂R^(v), —SO₂OR^(v), —NHC(O)R^(v), —CONR^(u)R^(v), —CONR^(u)R^(v),—SO₂NR^(u)R^(v), wherein R^(u) and R^(v) are independently selected fromhydrogen, C₁₋₁₂ alkyl, phenyl or phenyl-C₁₋₈ alkyl (e.g. benzyl). Where,for example, a group contains more than one substituent, differentsubstituents can have different R^(u) or R^(v) groups. For example, anaphthyl group may be substituted with three substituents: —SO₂NHPh,—CO₂Me group and —NH₂.

The term “alkyl” is used herein to refer to alkyl groups in bothstraight and branched forms. Unless stated otherwise, the alkyl groupmay be interrupted with 1, 2, 3 or 4 heteroatoms selected from O, NH orS. Unless stated otherwise, the alkyl group may also be interrupted with1, 2 or 3 double and/or triple bonds. However, the term “alkyl” usuallyrefers to alkyl groups having double or triple bond interruptions. Where“alkenyl” groups are specifically mentioned, this is not intended to beconstrued as a limitation on the definition of “alkyl” above.

Where reference is made to, for example, C₁₋₂₀ alkyl, it is meant thealkyl group may contain any number of carbon atoms between 1 and 20.Unless specifically stated otherwise, any reference to “alkyl” meansC₁₋₂₀ alkyl, preferably C₁₋₁₂ alkyl or C₁₋₆ alkyl.

The term “alkyl” also includes cycloalkyl groups. As used herein, theterm “cycloalkyl” includes cycloalkyl, polycycloalkyl, and cycloalkenylgroups, as well as combinations of these with linear alkyl groups, suchas cycloalkylalkyl groups. The cycloalkyl group may be interrupted with1, 2 or 3 heteroatoms selected from O, N or S and may be specificallyindicated as a heterocycloalkyl group. Examples of heterocycloalkylgroups are pyrrolidino, morpholino, piperidino etc. However, the term“cycloalkyl” usually refers to cycloalkyl groups having no heteroatominterruptions. Examples of cycloalkyl groups include cyclopentyl,cyclohexyl, cyclohexenyl, cyclohexylmethyl and adamantyl groups.

The term “arylalkyl” refers to groups such as benzyl, phenylethyl andnaphthylmethyl.

The term “halogen” or “halo” is used herein to refer to any of fluorine,chlorine, bromine and iodine. Usually, however, halogen refers tochlorine or fluorine substituents.

Any chiral compounds described herein have not been givenstereo-descriptors. However, when compounds may exist in stereoisomericforms, then all possible stereoisomers and mixtures thereof are included(e.g. enantiomers, diastereomers and all combinations including racemicmixtures etc.).

Likewise, when compounds may exist in a number of regioisomeric forms,then all possible regioisomers and mixtures thereof are included.

For the avoidance of doubt, the term “a” (or “an”), in phrases such as“comprising a”, means “at least one” and not “one and only one”. Wherethe term “at least one” is specifically used, this should not beconstrued as having a limitation on the definition of “a”.

Throughout the specification, the term “comprising”, or variations suchas “comprise” or “comprises”, should be construed as including a statedelement, integer or step, but not excluding any other element, integeror step.

Inks

The present invention also provides a solvent-based or an oil-based ink.Optionally, the ink is suitable for analog printing, such as offsetprinting. However, it will be appreciated that the ink may also besuitable for digital inkjet printheads, which do not require anaqueous-based ink for bubble generation. Examples of such printheads arepiezoelectric printheads and the Applicant's thermal bend actuatorprintheads described in more detail below.

Solvent-based and oil-based ink formulations suitable for analogprinting will be well known to the person skilled in the art. Suchprinting inks are typically comprised of four material categories,including: (a) dyes, which include pigments, toners and dyes; (b)vehicles, or varnishes, which act as carriers for the dyes during theprinting operation, and bind the dyes to the substrate upon drying; (c)solvents, which primarily assist in the formation of the vehicle, andreduce ink viscosity; and (d) additives, which influence theprintability, film characteristics, drying speed, and end-useproperties.

Printers

Analog printers, such as offset printers, have been known in the art fordecades and will be part of the skilled person's common generalknowledge.

As already mentioned, solvent-based inks described herein may be usedwith the Applicant's thermal bend actuator inkjet printheads. In thethermal bend actuator, there is typically provided a nozzle arrangementhaving a nozzle chamber containing ink and a thermal bend actuatorconnected to a paddle positioned within the chamber. The thermalactuator device is actuated so as to eject ink from the nozzle chamber.The preferred embodiment includes a particular thermal bend actuatorwhich includes a series of tapered portions for providing conductiveheating of a conductive trace. The actuator is connected to the paddlevia an arm received through a slotted wall of the nozzle chamber. Theactuator arm has a mating shape so as to mate substantially with thesurfaces of the slot in the nozzle chamber wall.

Turning initially to FIGS. 17( a)-(c), there is provided schematicillustrations of the basic operation of a nozzle arrangement of thisembodiment. A nozzle chamber 501 is provided filled with ink 502 bymeans of an ink inlet channel 503 which can be etched through a wafersubstrate on which the nozzle chamber 501 rests. The nozzle chamber 501further includes an ink ejection port 504 around which an ink meniscusforms.

Inside the nozzle chamber 501 is a paddle type device 507 which isinterconnected to an actuator 508 through a slot in the wall of thenozzle chamber 501. The actuator 508 includes a heater means e.g. 509located adjacent to an end portion of a post 510. The post 510 is fixedto a substrate.

When it is desired to eject a drop from the nozzle chamber 501, asillustrated in FIG. 17( b), the heater means 509 is heated so as toundergo thermal expansion. Preferably, the heater means 509 itself orthe other portions of the actuator 508 are built from materials having ahigh bend efficiency where the bend efficiency is defined as:

${{bend}\mspace{14mu}{efficiency}} = \frac{{{Young}'}s\mspace{14mu}{Modulus}\; \times \left( {{Coefficient}\mspace{14mu}{of}\mspace{14mu}{thermal}\mspace{14mu}{Expansion}} \right)}{{Density} \times {Specific}\mspace{14mu}{Heat}\mspace{14mu}{Capacity}}$

A suitable material for the heater elements is a copper nickel alloywhich can be formed so as to bend a glass material.

The heater means 509 is ideally located adjacent the end portion of thepost 510 such that the effects of activation are magnified at the paddleend 507 such that small thermal expansions near the post 510 result inlarge movements of the paddle end.

The heater means 509 and consequential paddle movement causes a generalincrease in pressure around the ink meniscus 505 which expands, asillustrated in FIG. 17( b), in a rapid manner. The heater current ispulsed and ink is ejected out of the port 504 in addition to flowing infrom the ink channel 503.

Subsequently, the paddle 507 is deactivated to again return to itsquiescent position. The deactivation causes a general reflow of the inkinto the nozzle chamber. The forward momentum of the ink outside thenozzle rim and the corresponding backflow results in a general neckingand breaking off of the drop 512 which proceeds to the print media. Thecollapsed meniscus 505 results in a general sucking of ink into thenozzle chamber 502 via the ink flow channel 503. In time, the nozzlechamber 501 is refilled such that the position in FIG. 17( a) is againreached and the nozzle chamber is subsequently ready for the ejection ofanother drop of ink.

FIG. 18 illustrates a side perspective view of the nozzle arrangement.FIG. 19 illustrates sectional view through an array of nozzlearrangement of FIG. 18. In these figures, the numbering of elementspreviously introduced has been retained.

Firstly, the actuator 508 includes a series of tapered actuator unitse.g. 515 which comprise an upper glass portion (amorphous silicondioxide) 516 formed on top of a titanium nitride layer 517.Alternatively a copper nickel alloy layer (hereinafter calledcupronickel) can be utilized which will have a higher bend efficiency.

The titanium nitride layer 517 is in a tapered form and, as such,resistive heating takes place near an end portion of the post 510.Adjacent titanium nitride/glass portions 515 are interconnected at ablock portion 519 which also provides a mechanical structural supportfor the actuator 508.

The heater means 509 ideally includes a plurality of the taperedactuator unit 515 which are elongate and spaced apart such that, uponheating, the bending force exhibited along the axis of the actuator 508is maximized. Slots are defined between adjacent tapered units 515 andallow for slight differential operation of each actuator 508 withrespect to adjacent actuators 508.

The block portion 519 is interconnected to an arm 520. The arm 520 is inturn connected to the paddle 507 inside the nozzle chamber 501 by meansof a slot e.g. 522 formed in the side of the nozzle chamber 501. Theslot 522 is designed generally to mate with the surfaces of the arm 520so as to minimize opportunities for the outflow of ink around the arm520. The ink is held generally within the nozzle chamber 501 via surfacetension effects around the slot 522.

When it is desired to actuate the arm 520, a conductive current ispassed through the titanium nitride layer 517 via within the blockportion 519 connecting to a lower CMOS layer 506 which provides thenecessary power and control circuitry for the nozzle arrangement. Theconductive current results in heating of the nitride layer 517 adjacentto the post 510 which results in a general upward bending of the arm 20and consequential ejection of ink out of the nozzle 504. The ejecteddrop is printed on a page in the usual manner for an inkjet printer aspreviously described.

An array of nozzle arrangements can be formed so as to create a singleprinthead. For example, in FIG. 24 there is illustrated a partlysectioned various array view which comprises multiple ink ejectionnozzle arrangements of FIG. 18 laid out in interleaved lines so as toform a printhead array. Of course, different types of arrays can beformulated including full color arrays etc.

The construction of the printhead system described can proceed utilizingstandard MEMS techniques through suitable modification of the steps asset out in U.S. Pat. No. 6,243,113 entitled “Image Creation Method andApparatus (IJ 41)” to the present applicant, the contents of which arefully incorporated by cross reference.

Substrates

As mentioned above, the dyes of the present invention are especiallysuitable for use in Hyperlabel™ and netpage systems. Such systems aredescribed in more detail below and in the patent applications listedabove, all of which are incorporated herein by reference in theirentirety.

Hence, the present invention provides a substrate having an IR-absorbingdye as described above disposed thereon or therein. Preferably, thesubstrate comprises an interface surface. Preferably, the dye isdisposed in the form of coded data suitable for use in netpage and/orHyperlabel™ systems. For example, the coded data may be indicative ofthe a plurality of locations and/or an identity of a product item.Preferably, the coded data is disposed over a substantial portion of aninterface surface of the substrate (e.g. greater than 20%, greater than50% or greater than 90% of the surface).

Preferably, the substrate is IR reflective so that the dye disposedthereon may be detected by a sensing device. The substrate may becomprised of any suitable material such as plastics (e.g. polyolefins,polyesters, polyamides etc.), paper, metal or combinations thereof. Thesubstrate may be laminated.

For netpage applications, the substrate is preferably a paper sheet. ForHyperlabel™ applications, the substrate is preferably a tag, a label, apackaging material or a surface of a product item. Typically, tags andlabels are comprised of plastics, paper or combinations thereof.

Netpage and Hyperlabel™

There now follows a detailed overview of netpage and Hyperlabel™. (Note:Memjet™ and Hyperlabel™ are trade marks of Silverbrook Research Pty Ltd,Australia). It will be appreciated that not every implementation willnecessarily embody all or even most of the specific details andextensions discussed below in relation to the basic system. However, thesystem is described in its most complete form to reduce the need forexternal reference when attempting to understand the context in whichthe preferred embodiments and aspects of the present invention operate.

In brief summary, the preferred form of the netpage system employs acomputer interface in the form of a mapped surface, that is, a physicalsurface which contains references to a map of the surface maintained ina computer system. The map references can be queried by an appropriatesensing device. Depending upon the specific implementation, the mapreferences may be encoded visibly or invisibly, and defined in such away that a local query on the mapped surface yields an unambiguous mapreference both within the map and among different maps. The computersystem can contain information about features on the mapped surface, andsuch information can be retrieved based on map references supplied by asensing device used with the mapped surface. The information thusretrieved can take the form of actions which are initiated by thecomputer system on behalf of the operator in response to the operator'sinteraction with the surface features.

In its preferred form, the netpage system relies on the production of,and human interaction with, netpages. These are pages of text, graphicsand images printed on ordinary paper, but which work like interactiveweb pages. Information is encoded on each page using ink which issubstantially invisible to the unaided human eye. The ink, however, andthereby the coded data, can be sensed by an optically imaging pen andtransmitted to the netpage system.

In the preferred form, active buttons and hyperlinks on each page can beclicked with the pen to request information from the network or tosignal preferences to a network server. In one embodiment, text writtenby hand on a netpage is automatically recognized and converted tocomputer text in the netpage system, allowing forms to be filled in. Inother embodiments, signatures recorded on a netpage are automaticallyverified, allowing e-commerce transactions to be securely authorized.

As illustrated in FIG. 1, a printed netpage 1 can represent aninteractive form which can be filled in by the user both physically, onthe printed page, and “electronically”, via communication between thepen and the netpage system. The example shows a “Request” formcontaining name and address fields and a submit button. The netpageconsists of graphic data 2 printed using visible ink, and coded data 3printed as a collection of tags 4 using invisible ink. The correspondingpage description 5, stored on the netpage network, describes theindividual elements of the netpage. In particular it describes the typeand spatial extent (zone) of each interactive element (i.e. text fieldor button in the example), to allow the netpage system to correctlyinterpret input via the netpage. The submit button 6, for example, has azone 7 which corresponds to the spatial extent of the correspondinggraphic 8.

As illustrated in FIG. 2, the netpage pen 101, a preferred form of whichis shown in FIGS. 6 and 7 and described in more detail below, works inconjunction with a personal computer (PC), Web terminal 75, or a netpageprinter 601. The netpage printer is an Internet-connected printingappliance for home, office or mobile use. The pen is wireless andcommunicates securely with the netpage network via a short-range radiolink 9. Short-range communication is relayed to the netpage network by alocal relay function which is either embedded in the PC, Web terminal ornetpage printer, or is provided by a separate relay device 44. The relayfunction can also be provided by a mobile phone or other device whichincorporates both short-range and longer-range communications functions.

In an alternative embodiment, the netpage pen utilises a wiredconnection, such as a USB or other serial connection, to the PC, Webterminal, netpage printer or relay device.

The netpage printer 601, a preferred form of which is shown in FIGS. 9to 11 and described in more detail below, is able to deliver,periodically or on demand, personalized newspapers, magazines, catalogs,brochures and other publications, all printed at high quality asinteractive netpages. Unlike a personal computer, the netpage printer isan appliance which can be, for example, wall-mounted adjacent to an areawhere the morning news is first consumed, such as in a user's kitchen,near a breakfast table, or near the household's point of departure forthe day. It also comes in tabletop, desktop, portable and miniatureversions.

Netpages printed at their point of consumption combine the ease-of-useof paper with the timeliness and interactivity of an interactive medium.

As shown in FIG. 2, the netpage pen 101 interacts with the coded data ona printed netpage 1 (or product item 201) and communicates theinteraction via a short-range radio link 9 to a relay. The relay sendsthe interaction to the relevant netpage page server 10 forinterpretation. In appropriate circumstances, the page server sends acorresponding message to application computer software running on anetpage application server 13. The application server may in turn send aresponse which is printed on the originating printer.

In an alternative embodiment, the PC, Web terminal, netpage printer orrelay device may communicate directly with local or remote applicationsoftware, including a local or remote Web server. Relatedly, output isnot limited to being printed by the netpage printer. It can also bedisplayed on the PC or Web terminal, and further interaction can bescreen-based rather than paper-based, or a mixture of the two.

The netpage system is made considerably more convenient in the preferredembodiment by being used in conjunction with high-speedmicroelectromechanical system (MEMS) based inkjet (Memjet™) printers. Inthe preferred form of this technology, relatively high-speed andhigh-quality printing is made more affordable to consumers. In itspreferred form, a netpage publication has the physical characteristicsof a traditional newsmagazine, such as a set of letter-size glossy pagesprinted in full color on both sides, bound together for easy navigationand comfortable handling.

The netpage printer exploits the growing availability of broadbandInternet access. Cable service is available to 95% of households in theUnited States, and cable modem service offering broadband Internetaccess is already available to 20% of these. The netpage printer canalso operate with slower connections, but with longer delivery times andlower image quality. Indeed, the netpage system can be enabled usingexisting consumer inkjet and laser printers, although the system willoperate more slowly and will therefore be less acceptable from aconsumer's point of view. In other embodiments, the netpage system ishosted on a private intranet. In still other embodiments, the netpagesystem is hosted on a single computer or computer-enabled device, suchas a printer.

Netpage publication servers 14 on the netpage network are configured todeliver print-quality publications to netpage printers. Periodicalpublications are delivered automatically to subscribing netpage printersvia pointcasting and multicasting Internet protocols. Personalizedpublications are filtered and formatted according to individual userprofiles.

A netpage printer can be configured to support any number of pens, and apen can work with any number of netpage printers. In the preferredimplementation, each netpage pen has a unique identifier. A householdmay have a collection of colored netpage pens, one assigned to eachmember of the family. This allows each user to maintain a distinctprofile with respect to a netpage publication server or applicationserver.

A netpage pen can also be registered with a netpage registration server11 and linked to one or more payment card accounts. This allowse-commerce payments to be securely authorized using the netpage pen. Thenetpage registration server compares the signature captured by thenetpage pen with a previously registered signature, allowing it toauthenticate the user's identity to an e-commerce server. Otherbiometrics can also be used to verify identity. A version of the netpagepen includes fingerprint scanning, verified in a similar way by thenetpage registration server.

Although a netpage printer may deliver periodicals such as the morningnewspaper without user intervention, it can be configured never todeliver unsolicited junk mail. In its preferred form, it only deliversperiodicals from subscribed or otherwise authorized sources. In thisrespect, the netpage printer is unlike a fax machine or e-mail accountwhich is visible to any junk mailer who knows the telephone number oremail address.

1 Netpage System Architecture

Each object model in the system is described using a Unified ModelingLanguage (UML) class diagram. A class diagram consists of a set ofobject classes connected by relationships, and two kinds ofrelationships are of interest here: associations and generalizations. Anassociation represents some kind of relationship between objects, i.e.between instances of classes. A generalization relates actual classes,and can be understood in the following way: if a class is thought of asthe set of all objects of that class, and class A is a generalization ofclass B, then B is simply a subset of A. The UML does not directlysupport second-order modelling—i.e. classes of classes.

Each class is drawn as a rectangle labelled with the name of the class.It contains a list of the attributes of the class, separated from thename by a horizontal line, and a list of the operations of the class,separated from the attribute list by a horizontal line. In the classdiagrams which follow, however, operations are never modelled.

An association is drawn as a line joining two classes, optionallylabelled at either end with the multiplicity of the association. Thedefault multiplicity is one. An asterisk (*) indicates a multiplicity of“many”, i.e. zero or more. Each association is optionally labelled withits name, and is also optionally labelled at either end with the role ofthe corresponding class. An open diamond indicates an aggregationassociation (“is-part-of”), and is drawn at the aggregator end of theassociation line.

A generalization relationship (“is-a”) is drawn as a solid line joiningtwo classes, with an arrow (in the form of an open triangle) at thegeneralization end.

When a class diagram is broken up into multiple diagrams, any classwhich is duplicated is shown with a dashed outline in all but the maindiagram which defines it. It is shown with attributes only where it isdefined.

1.1 Netpages

Netpages are the foundation on which a netpage network is built. Theyprovide a paper-based user interface to published information andinteractive services.

A netpage consists of a printed page (or other surface region) invisiblytagged with references to an online description of the page. The onlinepage description is maintained persistently by a netpage page server.The page description describes the visible layout and content of thepage, including text, graphics and images. It also describes the inputelements on the page, including buttons, hyperlinks, and input fields. Anetpage allows markings made with a netpage pen on its surface to besimultaneously captured and processed by the netpage system.

Multiple netpages can share the same page description. However, to allowinput through otherwise identical pages to be distinguished, eachnetpage is assigned a unique page identifier. This page ID hassufficient precision to distinguish between a very large number ofnetpages.

Each reference to the page description is encoded in a printed tag. Thetag identifies the unique page on which it appears, and therebyindirectly identifies the page description. The tag also identifies itsown position on the page. Characteristics of the tags are described inmore detail below.

Tags are printed in infrared-absorptive ink on any substrate which isinfrared-reflective, such as ordinary paper. Near-infrared wavelengthsare invisible to the human eye but are easily sensed by a solid-stateimage sensor with an appropriate filter.

A tag is sensed by an area image sensor in the netpage pen, and the tagdata is transmitted to the netpage system via the nearest netpageprinter. The pen is wireless and communicates with the netpage printervia a short-range radio link. Tags are sufficiently small and denselyarranged that the pen can reliably image at least one tag even on asingle click on the page. It is important that the pen recognize thepage ID and position on every interaction with the page, since theinteraction is stateless. Tags are error-correctably encoded to makethem partially tolerant to surface damage.

The netpage page server maintains a unique page instance for eachprinted netpage, allowing it to maintain a distinct set of user-suppliedvalues for input fields in the page description for each printednetpage.

The relationship between the page description, the page instance, andthe printed netpage is shown in FIG. 4. The printed netpage may be partof a printed netpage document 45. The page instance is associated withboth the netpage printer which printed it and, if known, the netpageuser who requested it.

As shown in FIG. 4, one or more netpages may also be associated with aphysical object such as a product item, for example when printed ontothe product item's label, packaging, or actual surface.

1.2 Netpage Tags

1.2.1 Tag Data Content

In a preferred form, each tag identifies the region in which it appears,and the location of that tag within the region. A tag may also containflags which relate to the region as a whole or to the tag. One or moreflag bits may, for example, signal a tag sensing device to providefeedback indicative of a function associated with the immediate area ofthe tag, without the sensing device having to refer to a description ofthe region. A netpage pen may, for example, illuminate an “active area”LED when in the zone of a hyperlink.

As will be more clearly explained below, in a preferred embodiment, eachtag contains an easily recognized invariant structure which aids initialdetection, and which assists in minimizing the effect of any warpinduced by the surface or by the sensing process. The tags preferablytile the entire page, and are sufficiently small and densely arrangedthat the pen can reliably image at least one tag even on a single clickon the page. It is important that the pen recognize the page ID andposition on every interaction with the page, since the interaction isstateless.

In a preferred embodiment, the region to which a tag refers coincideswith an entire page, and the region ID encoded in the tag is thereforesynonymous with the page ID of the page on which the tag appears. Inother embodiments, the region to which a tag refers can be an arbitrarysubregion of a page or other surface. For example, it can coincide withthe zone of an interactive element, in which case the region ID candirectly identify the interactive element.

In the preferred form, each tag contains 120 bits of information. Theregion ID is typically allocated up to 100 bits, the tag ID at least 16bits, and the remaining bits are allocated to flags etc. Assuming a tagdensity of 64 per square inch, a 16-bit tag ID supports a region size ofup to 1024 square inches. Larger regions can be mapped continuouslywithout increasing the tag ID precision simply by using abutting regionsand maps. The 100-bit region ID allows 2¹⁰⁰ (˜10³⁰ or a million trilliontrillion) different regions to be uniquely identified.

1.2.2 Tag Data Encoding

In one embodiment, the 120 bits of tag data are redundantly encodedusing a (15, 5) Reed-Solomon code. This yields 360 encoded bitsconsisting of 6 codewords of 15 4-bit symbols each. The (15, 5) codeallows up to 5 symbol errors to be corrected per codeword, i.e. it istolerant of a symbol error rate of up to 33% per codeword.

Each 4-bit symbol is represented in a spatially coherent way in the tag,and the symbols of the six codewords are interleaved spatially withinthe tag. This ensures that a burst error (an error affecting multiplespatially adjacent bits) damages a minimum number of symbols overall anda minimum number of symbols in any one codeword, thus maximising thelikelihood that the burst error can be fully corrected.

Any suitable error-correcting code can be used in place of a (15, 5)Reed-Solomon code, for example: a Reed-Solomon code with more or lessredundancy, with the same or different symbol and codeword sizes;another block code; or a different kind of code, such as a convolutionalcode (see, for example, Stephen B. Wicker, Error Control Systems forDigital Communication and Storage, Prentice-Hall 1995, the contents ofwhich a herein incorporated by reference thereto).

In order to support “single-click” interaction with a tagged region viaa sensing device, the sensing device must be able to see at least oneentire tag in its field of view no matter where in the region or at whatorientation it is positioned. The required diameter of the field of viewof the sensing device is therefore a function of the size and spacing ofthe tags.

1.2.3 Tag Structure

FIG. 5 a shows a tag 4, in the form of tag 726 with four perspectivetargets 17. The tag 726 represents sixty 4-bit Reed-Solomon symbols 747,for a total of 240 bits. The tag represents each “one” bit by thepresence of a mark 748, referred to as a macrodot, and each “zero” bitby the absence of the corresponding macrodot. FIG. 5 c shows a squaretiling 728 of nine tags, containing all “one” bits for illustrativepurposes. It will be noted that the perspective targets are designed tobe shared between adjacent tags. FIG. 5 d shows a square tiling of 16tags and a corresponding minimum field of view 193, which spans thediagonals of two tags.

Using a (15, 7) Reed-Solomon code, 112 bits of tag data are redundantlyencoded to produce 240 encoded bits. The four codewords are interleavedspatially within the tag to maximize resilience to burst errors.Assuming a 16-bit tag ID as before, this allows a region ID of up to 92bits.

The data-bearing macrodots 748 of the tag are designed to not overlaptheir neighbors, so that groups of tags cannot produce structures thatresemble targets. This also saves ink. The perspective targets allowdetection of the tag, so further targets are not required.

Although the tag may contain an orientation feature to allowdisambiguation of the four possible orientations of the tag relative tothe sensor, the present invention is concerned with embeddingorientation data in the tag data. For example, the four codewords can bearranged so that each tag orientation (in a rotational sense) containsone codeword placed at that orientation, as shown in FIG. 5 a, whereeach symbol is labelled with the number of its codeword (1-4) and theposition of the symbol within the codeword (A-O). Tag decoding thenconsists of decoding one codeword at each rotational orientation. Eachcodeword can either contain a single bit indicating whether it is thefirst codeword, or two bits indicating which codeword it is. The latterapproach has the advantage that if, say, the data content of only onecodeword is required, then at most two codewords need to be decoded toobtain the desired data. This may be the case if the region ID is notexpected to change within a stroke and is thus only decoded at the startof a stroke. Within a stroke only the codeword containing the tag ID isthen desired. Furthermore, since the rotation of the sensing devicechanges slowly and predictably within a stroke, only one codewordtypically needs to be decoded per frame.

It is possible to dispense with perspective targets altogether andinstead rely on the data representation being self-registering. In thiscase each bit value (or multi-bit value) is typically represented by anexplicit glyph, i.e. no bit value is represented by the absence of aglyph. This ensures that the data grid is well-populated, and thusallows the grid to be reliably identified and its perspective distortiondetected and subsequently corrected during data sampling. To allow tagboundaries to be detected, each tag data must contain a marker pattern,and these must be redundantly encoded to allow reliable detection. Theoverhead of such marker patterns is similar to the overhead of explicitperspective targets. Various such schemes are described in the presentapplicants' co-pending PCT application PCT/AU01/01274 filed 11 Oct.2001.

The arrangement 728 of FIG. 5 c shows that the square tag 726 can beused to fully tile or tesselate, i.e. without gaps or overlap, a planeof arbitrary size.

Although in preferred embodiments the tagging schemes described hereinencode a single data bit using the presence or absence of a singleundifferentiated macrodot, they can also use sets of differentiatedglyphs to represent single-bit or multi-bit values, such as the sets ofglyphs illustrated in the present applicants' co-pending PCT applicationPCT/AU01/01274 filed 11 Oct. 2001.

1.3 The Netpage Network

In a preferred embodiment, a netpage network consists of a distributedset of netpage page servers 10, netpage registration servers 11, netpageID servers 12, netpage application servers 13, netpage publicationservers 14, Web terminals 75, netpage printers 601, and relay devices 44connected via a network 19 such as the Internet, as shown in FIG. 3.

The netpage registration server 11 is a server which recordsrelationships between users, pens, printers, applications andpublications, and thereby authorizes various network activities. Itauthenticates users and acts as a signing proxy on behalf ofauthenticated users in application transactions. It also provideshandwriting recognition services. As described above, a netpage pageserver 10 maintains persistent information about page descriptions andpage instances. The netpage network includes any number of page servers,each handling a subset of page instances. Since a page server alsomaintains user input values for each page instance, clients such asnetpage printers send netpage input directly to the appropriate pageserver. The page server interprets any such input relative to thedescription of the corresponding page.

A netpage ID server 12 allocates document IDs 51 on demand, and providesload-balancing of page servers via its ID allocation scheme.

A netpage printer uses the Internet Distributed Name System (DNS), orsimilar, to resolve a netpage page ID 50 into the network address of thenetpage page server handling the corresponding page instance.

A netpage application server 13 is a server which hosts interactivenetpage applications. A netpage publication server 14 is an applicationserver which publishes netpage documents to netpage printers.

Netpage servers can be hosted on a variety of network server platformsfrom manufacturers such as IBM, Hewlett-Packard, and Sun. Multiplenetpage servers can run concurrently on a single host, and a singleserver can be distributed over a number of hosts. Some or all of thefunctionality provided by netpage servers, and in particular thefunctionality provided by the ID server and the page server, can also beprovided directly in a netpage appliance such as a netpage printer, in acomputer workstation, or on a local network.

1.4 The Netpage Printer

The netpage printer 601 is an appliance which is registered with thenetpage system and prints netpage documents on demand and viasubscription. Each printer has a unique printer ID 62, and is connectedto the netpage network via a network such as the Internet, ideally via abroadband connection.

Apart from identity and security settings in non-volatile memory, thenetpage printer contains no persistent storage. As far as a user isconcerned, “the network is the computer”. Netpages functioninteractively across space and time with the help of the distributednetpage page servers 10, independently of particular netpage printers.

The netpage printer receives subscribed netpage documents from netpagepublication servers 14. Each document is distributed in two parts: thepage layouts, and the actual text and image objects which populate thepages. Because of personalization, page layouts are typically specificto a particular subscriber and so are pointcast to the subscriber'sprinter via the appropriate page server. Text and image objects, on theother hand, are typically shared with other subscribers, and so aremulticast to all subscribers' printers and the appropriate page servers.

The netpage publication server optimizes the segmentation of documentcontent into pointcasts and multicasts. After receiving the pointcast ofa document's page layouts, the printer knows which multicasts, if any,to listen to.

Once the printer has received the complete page layouts and objects thatdefine the document to be printed, it can print the document.

The printer rasterizes and prints odd and even pages simultaneously onboth sides of the sheet. It contains duplexed print engine controllers760 and print engines utilizing Memjet™ printheads 350 for this purpose.

The printing process consists of two decoupled stages: rasterization ofpage descriptions, and expansion and printing of page images. The rasterimage processor (RIP) consists of one or more standard DSPs 757 runningin parallel. The duplexed print engine controllers consist of customprocessors which expand, dither and print page images in real time,synchronized with the operation of the printheads in the print engines.

Printers not enabled for IR printing have the option to print tags usingIR-absorptive black ink, although this restricts tags to otherwise emptyareas of the page. Although such pages have more limited functionalitythan IR-printed pages, they are still classed as netpages.

A normal netpage printer prints netpages on sheets of paper. Morespecialised netpage printers may print onto more specialised surfaces,such as globes. Each printer supports at least one surface type, andsupports at least one tag tiling scheme, and hence tag map, for eachsurface type. The tag map 811 which describes the tag tiling schemeactually used to print a document becomes associated with that documentso that the document's tags can be correctly interpreted.

FIG. 2 shows the netpage printer class diagram, reflectingprinter-related information maintained by a registration server 11 onthe netpage network.

1.5 The Netpage Pen

The active sensing device of the netpage system is typically a pen 101,which, using its embedded controller 134, is able to capture and decodeIR position tags from a page via an image sensor. The image sensor is asolid-state device provided with an appropriate filter to permit sensingat only near-infrared wavelengths. As described in more detail below,the system is able to sense when the nib is in contact with the surface,and the pen is able to sense tags at a sufficient rate to capture humanhandwriting (i.e. at 200 dpi or greater and 100 Hz or faster).Information captured by the pen is encrypted and wirelessly transmittedto the printer (or base station), the printer or base stationinterpreting the data with respect to the (known) page structure.

The preferred embodiment of the netpage pen operates both as a normalmarking ink pen and as a non-marking stylus. The marking aspect,however, is not necessary for using the netpage system as a browsingsystem, such as when it is used as an Internet interface. Each netpagepen is registered with the netpage system and has a unique pen ID 61.FIG. 14 shows the netpage pen class diagram, reflecting pen-relatedinformation maintained by a registration server 11 on the netpagenetwork.

When either nib is in contact with a netpage, the pen determines itsposition and orientation relative to the page. The nib is attached to aforce sensor, and the force on the nib is interpreted relative to athreshold to indicate whether the pen is “up” or “down”. This allows ainteractive element on the page to be ‘clicked’ by pressing with the pennib, in order to request, say, information from a network. Furthermore,the force is captured as a continuous value to allow, say, the fulldynamics of a signature to be verified.

The pen determines the position and orientation of its nib on thenetpage by imaging, in the infrared spectrum, an area 193 of the page inthe vicinity of the nib. It decodes the nearest tag and computes theposition of the nib relative to the tag from the observed perspectivedistortion on the imaged tag and the known geometry of the pen optics.Although the position resolution of the tag may be low, because the tagdensity on the page is inversely proportional to the tag size, theadjusted position resolution is quite high, exceeding the minimumresolution required for accurate handwriting recognition.

Pen actions relative to a netpage are captured as a series of strokes. Astroke consists of a sequence of time-stamped pen positions on the page,initiated by a pen-down event and completed by the subsequent pen-upevent. A stroke is also tagged with the page ID 50 of the netpagewhenever the page ID changes, which, under normal circumstances, is atthe commencement of the stroke.

Each netpage pen has a current selection 826 associated with it,allowing the user to perform copy and paste operations etc. Theselection is timestamped to allow the system to discard it after adefined time period. The current selection describes a region of a pageinstance. It consists of the most recent digital ink stroke capturedthrough the pen relative to the background area of the page. It isinterpreted in an application-specific manner once it is submitted to anapplication via a selection hyperlink activation.

Each pen has a current nib 824. This is the nib last notified by the pento the system. In the case of the default netpage pen described above,either the marking black ink nib or the non-marking stylus nib iscurrent. Each pen also has a current nib style 825. This is the nibstyle last associated with the pen by an application, e.g. in responseto the user selecting a color from a palette. The default nib style isthe nib style associated with the current nib. Strokes captured througha pen are tagged with the current nib style. When the strokes aresubsequently reproduced, they are reproduced in the nib style with whichthey are tagged.

Whenever the pen is within range of a printer with which it cancommunicate, the pen slowly flashes its “online” LED. When the pen failsto decode a stroke relative to the page, it momentarily activates its“error” LED. When the pen succeeds in decoding a stroke relative to thepage, it momentarily activates its “ok” LED.

A sequence of captured strokes is referred to as digital ink. Digitalink forms the basis for the digital exchange of drawings andhandwriting, for online recognition of handwriting, and for onlineverification of signatures.

The pen is wireless and transmits digital ink to the netpage printer viaa short-range radio link. The transmitted digital ink is encrypted forprivacy and security and packetized for efficient transmission, but isalways flushed on a pen-up event to ensure timely handling in theprinter.

When the pen is out-of-range of a printer it buffers digital ink ininternal memory, which has a capacity of over ten minutes of continuoushandwriting. When the pen is once again within range of a printer, ittransfers any buffered digital ink.

A pen can be registered with any number of printers, but because allstate data resides in netpages both on paper and on the network, it islargely immaterial which printer a pen is communicating with at anyparticular time.

A preferred embodiment of the pen is described in greater detail below,with reference to FIGS. 6 to 8.

1.6 Netpage Interaction

The netpage printer 601 receives data relating to a stroke from the pen101 when the pen is used to interact with a netpage 1. The coded data 3of the tags 4 is read by the pen when it is used to execute a movement,such as a stroke. The data allows the identity of the particular pageand associated interactive element to be determined and an indication ofthe relative positioning of the pen relative to the page to be obtained.The indicating data is transmitted to the printer, where it resolves,via the DNS, the page ID 50 of the stroke into the network address ofthe netpage page server 10 which maintains the corresponding pageinstance 830. It then transmits the stroke to the page server. If thepage was recently identified in an earlier stroke, then the printer mayalready have the address of the relevant page server in its cache. Eachnetpage consists of a compact page layout maintained persistently by anetpage page server (see below). The page layout refers to objects suchas images, fonts and pieces of text, typically stored elsewhere on thenetpage network.

When the page server receives the stroke from the pen, it retrieves thepage description to which the stroke applies, and determines whichelement of the page description the stroke intersects. It is then ableto interpret the stroke in the context of the type of the relevantelement.

A “click” is a stroke where the distance and time between the pen downposition and the subsequent pen up position are both less than somesmall maximum. An object which is activated by a click typicallyrequires a click to be activated, and accordingly, a longer stroke isignored. The failure of a pen action, such as a “sloppy” click, toregister is indicated by the lack of response from the pen's “ok” LED.

There are two kinds of input elements in a netpage page description:hyperlinks and form fields. Input through a form field can also triggerthe activation of an associated hyperlink.

2 Netpage Pen Description

2.1 Pen Mechanics

Referring to FIGS. 6 and 7, the pen, generally designated by referencenumeral 101, includes a housing 102 in the form of a plastics mouldinghaving walls 103 defining an interior space 104 for mounting the pencomponents. The pen top 105 is in operation rotatably mounted at one end106 of the housing 102. A semi-transparent cover 107 is secured to theopposite end 108 of the housing 102. The cover 107 is also of mouldedplastics, and is formed from semi-transparent material in order toenable the user to view the status of the LED mounted within the housing102. The cover 107 includes a main part 109 which substantiallysurrounds the end 108 of the housing 102 and a projecting portion 110which projects back from the main part 109 and fits within acorresponding slot 111 formed in the walls 103 of the housing 102. Aradio antenna 112 is mounted behind the projecting portion 110, withinthe housing 102. Screw threads 113 surrounding an aperture 113A on thecover 107 are arranged to receive a metal end piece 114, includingcorresponding screw threads 115. The metal end piece 114 is removable toenable ink cartridge replacement.

Also mounted within the cover 107 is a tri-color status LED 116 on aflex PCB 117. The antenna 112 is also mounted on the flex PCB 117. Thestatus LED 116 is mounted at the top of the pen 101 for good all-aroundvisibility.

The pen can operate both as a normal marking ink pen and as anon-marking stylus. An ink pen cartridge 118 with nib 119 and a stylus120 with stylus nib 121 are mounted side by side within the housing 102.Either the ink cartridge nib 119 or the stylus nib 121 can be broughtforward through open end 122 of the metal end piece 114, by rotation ofthe pen top 105. Respective slider blocks 123 and 124 are mounted to theink cartridge 118 and stylus 120, respectively. A rotatable cam barrel125 is secured to the pen top 105 in operation and arranged to rotatetherewith. The cam barrel 125 includes a cam 126 in the form of a slotwithin the walls 181 of the cam barrel. Cam followers 127 and 128projecting from slider blocks 123 and 124 fit within the cam slot 126.On rotation of the cam barrel 125, the slider blocks 123 or 124 moverelative to each other to project either the pen nib 119 or stylus nib121 out through the hole 122 in the metal end piece 114. The pen 101 hasthree states of operation. By turning the top 105 through 90° steps, thethree states are:

-   -   stylus 120 nib 121 out    -   ink cartridge 118 nib 119 out, and    -   neither ink cartridge 118 nib 119 out nor stylus 120 nib 121 out

A second flex PCB 129, is mounted on an electronics chassis 130 whichsits within the housing 102. The second flex PCB 129 mounts an infraredLED 131 for providing infrared radiation for projection onto thesurface. An image sensor 132 is provided mounted on the second flex PCB129 for receiving reflected radiation from the surface. The second flexPCB 129 also mounts a radio frequency chip 133, which includes an RFtransmitter and RF receiver, and a controller chip 134 for controllingoperation of the pen 101. An optics block 135 (formed from moulded clearplastics) sits within the cover 107 and projects an infrared beam ontothe surface and receives images onto the image sensor 132. Power supplywires 136 connect the components on the second flex PCB 129 to batterycontacts 137 which are mounted within the cam barrel 125. A terminal 138connects to the battery contacts 137 and the cam barrel 125. A threevolt rechargeable battery 139 sits within the cam barrel 125 in contactwith the battery contacts. An induction charging coil 140 is mountedabout the second flex PCB 129 to enable recharging of the battery 139via induction. The second flex PCB 129 also mounts an infrared LED 143and infrared photodiode 144 for detecting displacement in the cam barrel125 when either the stylus 120 or the ink cartridge 118 is used forwriting, in order to enable a determination of the force being appliedto the surface by the pen nib 119 or stylus nib 121. The IR photodiode144 detects light from the IR LED 143 via reflectors (not shown) mountedon the slider blocks 123 and 124.

Rubber grip pads 141 and 142 are provided towards the end 108 of thehousing 102 to assist gripping the pen 101, and top 105 also includes aclip 142 for clipping the pen 101 to a pocket.

3.2 Pen Controller

The pen 101 is arranged to determine the position of its nib (stylus nib121 or ink cartridge nib 119) by imaging, in the infrared spectrum, anarea of the surface in the vicinity of the nib. It records the locationdata from the nearest location tag, and is arranged to calculate thedistance of the nib 121 or 119 from the location tab utilising optics135 and controller chip 134. The controller chip 134 calculates theorientation of the pen and the nib-to-tag distance from the perspectivedistortion observed on the imaged tag.

Utilising the RF chip 133 and antenna 112 the pen 101 can transmit thedigital ink data (which is encrypted for security and packaged forefficient transmission) to the computing system.

When the pen is in range of a receiver, the digital ink data istransmitted as it is formed. When the pen 101 moves out of range,digital ink data is buffered within the pen 101 (the pen 101 circuitryincludes a buffer arranged to store digital ink data for approximately12 minutes of the pen motion on the surface) and can be transmittedlater.

The controller chip 134 is mounted on the second flex PCB 129 in the pen101. FIG. 8 is a block diagram illustrating in more detail thearchitecture of the controller chip 134. FIG. 8 also showsrepresentations of the RF chip 133, the image sensor 132, the tri-colorstatus LED 116, the IR illumination LED 131, the IR force sensor LED143, and the force sensor photodiode 144.

The pen controller chip 134 includes a controlling processor 145. Bus146 enables the exchange of data between components of the controllerchip 134. Flash memory 147 and a 512 KB DRAM 148 are also included. Ananalog-to-digital converter 149 is arranged to convert the analog signalfrom the force sensor photodiode 144 to a digital signal.

An image sensor interface 152 interfaces with the image sensor 132. Atransceiver controller 153 and base band circuit 154 are also includedto interface with the RF chip 133 which includes an RF circuit 155 andRF resonators and inductors 156 connected to the antenna 112.

The controlling processor 145 captures and decodes location data fromtags from the surface via the image sensor 132, monitors the forcesensor photodiode 144, controls the LEDs 116, 131 and 143, and handlesshort-range radio communication via the radio transceiver 153. It is amedium-performance (˜40 MHz) general-purpose RISC processor.

The processor 145, digital transceiver components (transceivercontroller 153 and baseband circuit 154), image sensor interface 152,flash memory 147 and 512 KB DRAM 148 are integrated in a singlecontroller ASIC. Analog RF components (RF circuit 155 and RF resonatorsand inductors 156) are provided in the separate RF chip.

The image sensor is a CCD or CMOS image sensor. Depending on taggingscheme, it has a size ranging from about 100×100 pixels to 200×200pixels. Many miniature CMOS image sensors are commercially available,including the National Semiconductor LM9630.

The controller ASIC 134 enters a quiescent state after a period ofinactivity when the pen 101 is not in contact with a surface. Itincorporates a dedicated circuit 150 which monitors the force sensorphotodiode 144 and wakes up the controller 134 via the power manager 151on a pen-down event.

The radio transceiver communicates in the unlicensed 900 MHz bandnormally used by cordless telephones, or alternatively in the unlicensed2.4 GHz industrial, scientific and medical (ISM) band, and usesfrequency hopping and collision detection to provide interference-freecommunication.

In an alternative embodiment, the pen incorporates an Infrared DataAssociation (IrDA) interface for short-range communication with a basestation or netpage printer.

In a further embodiment, the pen 101 includes a pair of orthogonalaccelerometers mounted in the normal plane of the pen 101 axis. Theaccelerometers 190 are shown in FIGS. 7 and 8 in ghost outline.

The provision of the accelerometers enables this embodiment of the pen101 to sense motion without reference to surface location tags, allowingthe location tags to be sampled at a lower rate. Each location tag IDcan then identify an object of interest rather than a position on thesurface. For example, if the object is a user interface input element(e.g. a command button), then the tag ID of each location tag within thearea of the input element can directly identify the input element.

The acceleration measured by the accelerometers in each of the x and ydirections is integrated with respect to time to produce aninstantaneous velocity and position.

Since the starting position of the stroke is not known, only relativepositions within a stroke are calculated. Although position integrationaccumulates errors in the sensed acceleration, accelerometers typicallyhave high resolution, and the time duration of a stroke, over whicherrors accumulate, is short.

3 Netpage Printer Description

3.1 Printer Mechanics

The vertically-mounted netpage wallprinter 601 is shown fully assembledin FIG. 9. It prints netpages on Letter/A4 sized media using duplexed8½″ Memjet™ print engines 602 and 603, as shown in FIGS. 10 and 10 a. Ituses a straight paper path with the paper 604 passing through theduplexed print engines 602 and 603 which print both sides of a sheetsimultaneously, in full color and with full bleed.

An integral binding assembly 605 applies a strip of glue along one edgeof each printed sheet, allowing it to adhere to the previous sheet whenpressed against it. This creates a final bound document 618 which canrange in thickness from one sheet to several hundred sheets.

The replaceable ink cartridge 627, shown in FIG. 12 coupled with theduplexed print engines, has bladders or chambers for storing fixative,adhesive, and cyan, magenta, yellow, black and infrared inks. Thecartridge also contains a micro air filter in a base molding. The microair filter interfaces with an air pump 638 inside the printer via a hose639. This provides filtered air to the printheads to prevent ingress ofmicro particles into the Memjet™ printheads 350 which might otherwiseclog the printhead nozzles. By incorporating the air filter within thecartridge, the operational life of the filter is effectively linked tothe life of the cartridge. The ink cartridge is a fully recyclableproduct with a capacity for printing and gluing 3000 pages (1500sheets).

Referring to FIG. 10, the motorized media pick-up roller assembly 626pushes the top sheet directly from the media tray past a paper sensor onthe first print engine 602 into the duplexed Memjet™ printhead assembly.The two Memjet™ print engines 602 and 603 are mounted in an opposingin-line sequential configuration along the straight paper path. Thepaper 604 is drawn into the first print engine 602 by integral, poweredpick-up rollers 626. The position and size of the paper 604 is sensedand full bleed printing commences. Fixative is printed simultaneously toaid drying in the shortest possible time.

The paper exits the first Memjet™ print engine 602 through a set ofpowered exit spike wheels (aligned along the straight paper path), whichact against a rubberized roller. These spike wheels contact the ‘wet’printed surface and continue to feed the sheet 604 into the secondMemjet™ print engine 603.

Referring to FIGS. 10 and 10 a, the paper 604 passes from the duplexedprint engines 602 and 603 into the binder assembly 605. The printed pagepasses between a powered spike wheel axle 670 with a fibrous supportroller and another movable axle with spike wheels and a momentary actionglue wheel. The movable axle/glue assembly 673 is mounted to a metalsupport bracket and it is transported forward to interface with thepowered axle 670 via gears by action of a camshaft. A separate motorpowers this camshaft.

The glue wheel assembly 673 consists of a partially hollow axle 679 witha rotating coupling for the glue supply hose 641 from the ink cartridge627. This axle 679 connects to a glue wheel, which absorbs adhesive bycapillary action through radial holes. A molded housing 682 surroundsthe glue wheel, with an opening at the front. Pivoting side moldings andsprung outer doors are attached to the metal bracket and hinge outsideways when the rest of the assembly 673 is thrust forward. Thisaction exposes the glue wheel through the front of the molded housing682. Tension springs close the assembly and effectively cap the gluewheel during periods of inactivity.

As the sheet 604 passes into the glue wheel assembly 673, adhesive isapplied to one vertical edge on the front side (apart from the firstsheet of a document) as it is transported down into the binding assembly605.

4 Product Tagging

Automatic identification refers to the use of technologies such as barcodes, magnetic stripe cards, smartcards, and RF transponders, to(semi-)automatically identify objects to data processing systems withoutmanual keying.

For the purposes of automatic identification, a product item is commonlyidentified by a 12-digit Universal Product Code (UPC), encodedmachine-readably in the form of a printed bar code. The most common UPCnumbering system incorporates a 5-digit manufacturer number and a5-digit item number. Because of its limited precision, a UPC is used toidentify a class of product rather than an individual product item. TheUniform Code Council and EAN International define and administer the UPCand related codes as subsets of the 14-digit Global Trade Item Number(GTIN).

Within supply chain management, there is considerable interest inexpanding or replacing the UPC scheme to allow individual product itemsto be uniquely identified and thereby tracked. Individual item taggingcan reduce “shrinkage” due to lost, stolen or spoiled goods, improve theefficiency of demand-driven manufacturing and supply, facilitate theprofiling of product usage, and improve the customer experience.

There are two main contenders for individual item tagging: optical tagsin the form of so-called two-dimensional bar codes, and radio frequencyidentification (RFID) tags. For a detailed description of RFID tags,refer to Klaus Finkenzeller, RFID Handbook, John Wiley & Son (1999), thecontents of which are herein incorporated by cross-reference. Opticaltags have the advantage of being inexpensive, but require opticalline-of-sight for reading. RFID tags have the advantage of supportingomnidirectional reading, but are comparatively expensive. The presenceof metal or liquid can seriously interfere with RFID tag performance,undermining the omnidirectional reading advantage. Passive(reader-powered) RFID tags are projected to be priced at 10 cents eachin multi-million quantities by the end of 2003, and at 5 cents each soonthereafter, but this still falls short of the sub-one-cent industrytarget for low-price items such as grocery. The read-only nature of mostoptical tags has also been cited as a disadvantage, since status changescannot be written to a tag as an item progresses through the supplychain. However, this disadvantage is mitigated by the fact that aread-only tag can refer to information maintained dynamically on anetwork.

The Massachusetts Institute of Technology (MIT) Auto-ID Center hasdeveloped a standard for a 96-bit Electronic Product Code (EPC), coupledwith an Internet-based Object Name Service (ONS) and a Product MarkupLanguage (PML). Once an EPC is scanned or otherwise obtained, it is usedto look up, possibly via the ONS, matching product information portablyencoded in PML. The EPC consists of an 8-bit header, a 28-bit EPCmanager, a 24-bit object class, and a 36-bit serial number. For adetailed description of the EPC, refer to Brock, D. L., The ElectronicProduct Code (EPC), MIT Auto-ID Center (January 2001), the contents ofwhich are herein incorporated by cross-reference. The Auto-ID Center hasdefined a mapping of the GTIN onto the EPC to demonstrate compatibilitybetween the EPC and current practices Brock, D. L., Integrating theElectronic Product Code (EPC) and the Global Trade Item Number (GTIN),MIT Auto-ID Center (November 2001), the contents of which are hereinincorporated by cross-reference. The EPC is administered by EPCglobal,an EAN-UCC joint venture.

EPCs are technology-neutral and can be encoded and carried in manyforms. The Auto-ID Center strongly advocates the use of low-cost passiveRFID tags to carry EPCs, and has defined a 64-bit version of the EPC toallow the cost of RFID tags to be minimized in the short term. Fordetailed description of low-cost RFID tag characteristics, refer toSarma, S., Towards the 5c Tag, MIT Auto-ID Center (November 2001), thecontents of which are herein incorporated by cross-reference. For adescription of a commercially-available low-cost passive RFID tag, referto 915 MHz RFID Tag, Alien Technology (2002), the contents of which areherein incorporated by cross-reference. For detailed description of the64-bit EPC, refer to Brock, D. L., The Compact Electronic Product Code,MIT Auto-ID Center (November 2001), the contents of which are hereinincorporated by cross-reference.

EPCs are intended not just for unique item-level tagging and tracking,but also for case-level and pallet-level tagging, and for tagging ofother logistic units of shipping and transportation such as containersand trucks. The distributed PML database records dynamic relationshipsbetween items and higher-level containers in the packaging, shipping andtransportation hierarchy.

4.1 Hyperlabel™ Tagging in the Supply Chain

Using an invisible (e.g. infrared) tagging scheme to uniquely identify aproduct item has the significant advantage that it allows the entiresurface of a product to be tagged, or a significant portion thereof,without impinging on the graphic design of the product's packaging orlabelling. If the entire product surface is tagged, then the orientationof the product doesn't affect its ability to be scanned, i.e. asignificant part of the line-of-sight disadvantage of a visible bar codeis eliminated. Furthermore, since the tags are small and massivelyreplicated, label damage no longer prevents scanning.

Hyperlabel tagging, then, consists of covering a large proportion of thesurface of a product item with optically-readable invisible tags. EachHyperlabel tag uniquely identifies the product item on which it appears.The Hyperlabel may directly encode the product code (e.g. EPC) of theitem, or may encode a surrogate ID which in turn identifies the productcode via a database lookup. Each Hyperlabel tag also optionallyidentifies its own position on the surface of the product item, toprovide the downstream consumer benefits of netpage interactivitydescribed earlier.

Hyperlabel tags are applied during product manufacture and/or packagingusing digital printers. These may be add-on infrared printers whichprint the Hyperlabel tags after the text and graphics have been printedby other means, or integrated color and infrared printers which printthe Hyperlabel tags, text and graphics simultaneously. Digitally-printedtext and graphics may include everything on the label or packaging, ormay consist only of the variable portions, with other portions stillprinted by other means.

4.2 Hyperlabel™ Tagging

As shown in FIG. 13, a product's unique item ID 215 may be seen as aspecial kind of unique object ID 210. The Electronic Product Code (EPC)220 is one emerging standard for an item ID. An item ID typicallyconsists of a product ID 214 and a serial number 213. The product IDidentifies a class of product, while the serial number identifies aparticular instance of that class, i.e. an individual product item. Theproduct ID in turn typically consists of a manufacturer number 211 and aproduct class number 212. The best-known product ID is the EAN.UCCUniversal Product Code (UPC) 221 and its variants.

As shown in FIG. 14, a Hyperlabel tag 202 encodes a page ID (or regionID) 50 and a two-dimensional (2D) position 86. The region ID identifiesthe surface region containing the tag, and the position identifies thetag's position within the two-dimensional region. Since the surface inquestion is the surface of a physical product item 201, it is useful todefine a one-to-one mapping between the region ID and the unique objectID 210, and more specifically the item ID 215, of the product item.Note, however, that the mapping can be many-to-one without compromisingthe utility of the Hyperlabel tag. For example, each panel of a productitem's packaging could have a different region ID 50. Conversely, theHyperlabel tag may directly encode the item ID, in which case the regionID contains the item ID, suitably prefixed to decouple item IDallocation from general netpage region ID allocation. Note that theregion ID uniquely distinguishes the corresponding surface region fromall other surface regions identified within the global netpage system.

The item ID 215 is preferably the EPC 220 proposed by the Auto-IDCenter, since this provides direct compatibility between Hyperlabel tagsand EPC-carrying RFID tags.

In FIG. 14 the position 86 is shown as optional. This is to indicatethat much of the utility of the Hyperlabel tag in the supply chainderives from the region ID 50, and the position may be omitted if notdesired for a particular product.

For interoperability with the netpage system, the Hyperlabel tag 202 isa netpage tag 4, i.e. it has the logical structure, physical layout andsemantics of a netpage tag.

When a netpage sensing device such as the netpage pen 101 images anddecodes a Hyperlabel tag, it uses the position and orientation of thetag in its field of view and combines this with the position encoded inthe tag to compute its own position relative to the tag. As the sensingdevice is moved relative to a Hyperlabel tagged surface region, it isthereby able to track its own motion relative to the region and generatea set of timestamped position samples representative of its time-varyingpath. When the sensing device is a pen, then the path consists of asequence of strokes, with each stroke starting when the pen makescontact with the surface, and ending when the pen breaks contact withthe surface.

When a stroke is forwarded to the page server 10 responsible for theregion ID, the server retrieves a description of the region keyed byregion ID, and interprets the stroke in relation to the description. Forexample, if the description includes a hyperlink and the strokeintersects the zone of the hyperlink, then the server may interpret thestroke as a designation of the hyperlink and activate the hyperlink.

4.3 Hyperlabel™ Tag Printing

A Hyperlabel tag printer is a digital printer which prints Hyperlabeltags onto the label, packaging or actual surface of a product before,during or after product manufacture and/or assembly. It is a specialcase of a netpage printer 601. It is capable of printing a continuouspattern of Hyperlabel tags onto a surface, typically using anear-infrared-absorptive ink. In high-speed environments, the printerincludes hardware which accelerates tag rendering. This typicallyincludes real-time Reed-Solomon encoding of variable tag data such astag position, and real-time template-based rendering of the actual tagpattern at the dot resolution of the printhead.

The printer may be an add-on infrared printer which prints theHyperlabel tags after text and graphics have been printed by othermeans, or an integrated color and infrared printer which prints theHyperlabel tags, text and graphics simultaneously. Digitally-printedtext and graphics may include everything on the label or packaging, ormay consist only of the variable portions, with other portions stillprinted by other means. Thus a Hyperlabel tag printer with an infraredand black printing capability can displace an existing digital printerused for variable data printing, such as a conventional thermal transferor inkjet printer.

For the purposes of the following discussion, any reference to printingonto an item label is intended to include printing onto the itempackaging in general, or directly onto the item surface. Furthermore,any reference to an item ID 215 is intended to include a region ID 50(or collection of per-panel region ids), or a component thereof.

The printer is typically controlled by a host computer, which suppliesthe printer with fixed and/or variable text and graphics as well as itemids for inclusion in the Hyperlabel tags. The host may provide real-timecontrol over the printer, whereby it provides the printer with data inreal time as printing proceeds. As an optimisation, the host may providethe printer with fixed data before printing begins, and only providevariable data in real time. The printer may also be capable ofgenerating per-item variable data based on parameters provided by thehost. For example, the host may provide the printer with a base item IDprior to printing, and the printer may simply increment the base item IDto generate successive item ids. Alternatively, memory in the inkcartridge or other storage medium inserted into the printer may providea source of unique item ids, in which case the printer reports theassignment of items ids to the host computer for recording by the host.

Alternatively still, the printer may be capable of reading apre-existing item ID from the label onto which the Hyperlabel tags arebeing printed, assuming the unique ID has been applied in some form tothe label during a previous manufacturing step. For example, the item IDmay already be present in the form of a visible 2D bar code, or encodedin an RFID tag. In the former case the printer can include an opticalbar code scanner. In the latter case it can include an RFID reader.

The printer may also be capable of rendering the item ID in other forms.For example, it may be capable of printing the item ID in the form of a2D bar code, or of printing the product ID component of the item ID inthe form of a ID bar code, or of writing the item ID to a writable orwrite-once RFID tag.

4.4 Hyperlabel™ Tag Scanning

Item information typically flows to the product server in response tosituated scan events, e.g. when an item is scanned into inventory ondelivery; when the item is placed on a retail shelf, and when the itemis scanned at point of sale. Both fixed and hand-held scanners may beused to scan Hyperlabel tagged product items, using both laser-based 2Dscanning and 2D image-sensor-based scanning, using similar or the sametechniques as employed in the netpage pen.

As shown in FIG. 16, both a fixed scanner 254 and a hand-held scanner252 communicate scan data to the product server 251. The product servermay in turn communicate product item event data to a peer product server(not shown), or to a product application server 250, which may implementsharing of data with related product servers. For example, stockmovements within a retail store may be recorded locally on the retailstore's product server, but the manufacturer's product server may benotified once a product item is sold.

4.5 Hyperlabel™ Tag-Based Netpage Interactions

A product item whose labelling, packaging or actual surface has beenHyperlabel tagged provides the same level of interactivity as any othernetpage.

There is a strong case to be made for netpage-compatible producttagging. Netpage turns any printed surface into a finely differentiatedgraphical user interface akin to a Web page, and there are manyapplications which map nicely onto the surface of a product. Theseapplications include obtaining product information of various kinds(nutritional information; cooking instructions; recipes; relatedproducts; use-by dates; servicing instructions; recall notices); playinggames; entering competitions; managing ownership (registration; query,such as in the case of stolen goods; transfer); providing productfeedback; messaging; and indirect device control. If, on the other hand,the product tagging is undifferentiated, such as in the case of anundifferentiated 2D barcode or RFID-carried item ID, then the burden ofinformation navigation is transferred to the information deliverydevice, which may significantly increase the complexity of the userexperience or the required sophistication of the delivery device userinterface.

The invention will now be described with reference to the followingexamples. However, it will of course be appreciated that this inventionmay be embodied in many other forms without departing from the scope ofthe invention, as defined in the accompanying claims.

4.7 Hyperlabel™ Tags Encoding Layout Data

As described above, a Hyperlabel tagged surface carries a continuousarray of Hyperlabel tags. These typically encode the product item'sunique identifier (e.g. EPC) and digital signature(s), as well as atwo-dimensional coordinate grid.

A range of analog printing processes are used to produce labels andpackaging, including gravure, letterpress, offset, flexographic, anddigital. Some packaging is produced using multiple processes insequence. For example, package graphics may be printed on a web-fedflexographic press, while batch and expiry information is digitallyprinted onto each finished package using laser marking or inkjet.

Hyperlabel tags may be printed digitally using an add-on digitalprinter, placed either before or after the colour press. The Hyperlabeldigital add-on printer can utilise a Memjet printhead as describedearlier, or any of a range of commercially-available laser and inkjetprintheads such as from HP Indigo, Xaar, Xeikon, Agfa.dotrix, VideoJet,Mark Andy, etc. The Hyperlabel digital printer can be web-fed orsheet-fed according to the line to which it is added.

The add-on digital printer must be synchronised with the colour press toensure registration between printed graphics and Hyperlabel tags. Thiscan be achieved by conventional means, for example by generating anelectronic signal in the colour press synchronised with the printing ofan impression, and feeding that signal to the Hyperlabel printer.Alternatively, the Hyperlabel printer can optically detect printedfiducials produced by the colour press, as is sometimes used tosynchronise die cutters with a colour press.

The Hyperlabel printer can be merely approximately synchronised with thecolour press, and fine synchronisation can be achieved by measuring theactual registration achieved and recording a corresponding offset in theNetpage server database, as described elsewhere in relation topre-tagged Netpage blanks. The measurement can take place while thepackaging is still in the form of web or sheet media, or after beingfolded or applied to the product item. In the former case detection ofthe registration of the product graphics is still required, for examplevia fiducials as mentioned above. In the latter case registration of theproduct graphics is determined by virtue of the individual packagepassing along the line. This may be intrinsic in the design of the line,or may involve a photodetector to detect passage of the item. Detectionof the Hyperlabel tag pattern uses a Hyperlabel reader in both cases.

Web or sheet media can be pre-printed (or printed in-line by an upstreamdigital Hyperlabel printer) with Hyperlabel tags which encode acontinuous and large two-dimensional coordinate space and no explicititem identifiers. After passing through the colour press, each item'spackaging will have a different range of coordinates. These can bedetected as described above and recorded in the Netpage server database(and/or a product database) as being associated with the item and itsitem identifier. When a Hyperlabel tag on a particular item issubsequently read, its coordinate can be translated into an itemidentifier by querying the Netpage server (or product server).

A digital printhead can be adapted to print both product graphics andHyperlabel tags, as described earlier in relation to Memjet digitalprintheads. Other digital printheads can be similarly adapted throughthe provision for an extra, infrared, ink channel.

As an alternative to digitally printing Hyperlabel tags, Hyperlabel tagscan be printed using an analog process such as gravure, letterpress,offset or flexographic, for example on the same colour press used toprint product graphics. A colour press is adapted to print Hyperlabeltags through the provision of an extra, infrared, ink channel; i.e.through the provision of an extra plate which bears the image of theHyperlabel tags. The Hyperlabel plate can be produced by conventionalmeans, such as computer to film (CtF) or direct computer to plate (CtP).It will be appreciated that any of the Hyperlabel tags 202 describedhereinafter may be printed with inks according to the present invention.

Note that although Hyperlabel tags are ideally printed using aninvisible ink such as infrared ink, they can also be printed using avisible ink such as a coloured, black or gray ink. And althoughHyperlabel tags are ideally printed over the entire product package,they can also be printed selectively in specific areas. And althoughHyperlabel tags are ideally position-indicating, they can also beobject-indicating, as described elsewhere.

If Hyperlabel tags are printed using an analog press, then it isimpractical to provide each product item package with a unique serialnumber. However, the Hyperlabel tags can still encode the productidentifier portion of the item identifier and the usual two-dimensionalcoordinate grid. In addition, the tags must encode a unique layoutnumber which identifies the particular graphic (and interactive) layoutof the package. The Hyperlabel tags also encode a flag which allows anyHyperlabel reader to determine that the tags encode a layout numberrather than a serial number. The layout number only needs to be uniquefor different layouts associated with the same product identifier. Itforms a unique layout identifier when paired with a product identifier,as shown in FIG. 20. The layout number changes precisely when new platesare produced for a new graphic package design, such as for a particularpromotion or a particular geographic region. CtP makes frequent layoutchanges particularly convenient.

Analog-printed Hyperlabel tags can thus encode a layout identifierrather than an item identifier, as shown in FIG. 21. During a subsequentinteraction with a product item via a Hyperlabel reader, the layoutidentifier is used to retrieve the corresponding layout to allow theinteraction to be interpreted in the usual way. For convenience we referto such Hyperlabel tags as “layout-indicating” (to distinguish then fromitem-indicating Hyperlabel tags), and the data sent from the Hyperlabelreader to the Netpage server as “layout data”.

It is convenient to encode a product identifier in the layoutidentifier, since it allows a Hyperlabel reader to identify the product.However, it is also possible to encode a pure layout identifier inHyperlabel tags which identifies the layout but does not directlyidentify the product. Equivalently, it is possible to encode a purecoordinate grid in the Hyperlabel tags and use the range of thecoordinates to identify the corresponding layout. Thus all product itemssharing the same graphic package layout would share the same coordinategrid range, and a change in layout would result in a change incoordinate grid range. The equivalence of a pure coordinate grid and acoordinate grid coupled with an item or layout identifier is discussedin the cross-referenced applications.

Layout-indicating Hyperlabel tags can confer interactivity in the usualway via the layout identifier and the coordinate grid that they encode,and product identification (but not product item identification) via theproduct identifier they encode.

Identification of individual product items is still important. Itconfers the various supply chain benefits discussed at length elsewhere,and plays a role in various interactive scenarios. For example, someproduct promotions may ideally be single-use, such as entering acompetition or redeeming a token.

In addition, item-level identification, coupled with a digital signatureunique to the item, allows product item authentication. In the followingdiscussion, item-indicating Hyperlabel tags typically carry the digitalsignature(s) of the item in the usual way.

4.8 Location-Indicating Tags in Conjunction with Alternative ItemIdentifiers

Item-level identification can be provided in a variety of ways inconjunction with location-indicating or layout-indicating Hyperlabeltags. For example, location- or layout-indicating tags can be printedover the whole package, while item-indicating tags can be printed inonly a small area. This has the benefit that the corresponding digitalHyperlabel printer can be relatively small, since it is no longerrequired to print tags across the full width of a web or sheet, but onlyonto a small area of each package. Digital printers for printing batchand expiry information, as well as for printing item-level indicia suchas two-dimensional barcodes, are already part of conventional packagingworkflows. A small-area digital Hyperlabel printer can be incorporatedin a similar place in such packaging workflows.

Item-level identification may be provided using a conventionalradio-frequency identification (RFID) tag 210 or a linear ortwo-dimensional barcode 211 (FIGS. 22 and 23). Even if such carriers arepresent on a package, it can be convenient to also provideitem-indicating Hyperlabel tags 202 in a small area, since these arereadable by a standard Hyperlabel reader. Any Hyperlabel hyperlink whichrequires item-level identification, such as competition entry, tokenredemption or item authentication, can be implemented in theitem-indicating Hyperlabel area. Alternatively, the user can be promptedto click in the item-indicating Hyperlabel area to identify the item,after invoking a single-use hyperlink elsewhere on the product whereonly layout-indicating tags are present.

If the item-level identification carrier is an RFID tag 210, then theHyperlabel reader 101 can incorporate an RFID tag reader to allow it toobtain the item identifier from the RFID tag 210 at the same time as itreads location- or layout-indicating Hyperlabel tags 202. Having readthe data contained in the Hyperlabel tag(s) 4 and the RFID tag 210, theHyperlabel reader sends “indicating data”, which identifies the item IDand the position of the reader, to the Netpage server. In the case thatthe Hyperlabel tags 202 are location-indicating tags, the Netpage servercan identify the layout from the item ID contained in the indicatingdata. Thus a Hyperlabel hyperlink requiring item-level identificationcan be implemented via a combination of location- or layout-indicatingHyperlabel tags 202 and an RFID tag 210. Accordingly, the Hyperlabelreader 101 may comprises an optical sensor for sensing the Hyperlabeltags 202, an RFID transceiver for sensing the RFID tag, a processor forgenerating the indicating data and means for communicating with theNetpage server (e.g. by wireless or wired communication)

Equivalently, a device already enabled with an RFID reader to providegross interactivity with an RFID-tagged object or surface can beaugmented with a Hyperlabel reader to allow it to support much morefine-grained interactivity with an RFID- and Hyperlabel-tagged object orsurface.

If the item-level identification carrier is a visible barcode 211, theninvisible item-indicating Hyperlabel tags 202 can be provided in thesame area as the barcode. This allows a user of a Hyperlabel reader 101to click on the barcode to obtain the item identifier, even though theHyperlabel reader 101 may be unable to read the (arbitrarily large)visible barcode. Alternatively or additionally, item-indicating tags canbe printed adjacent to the barcode using the same visible ink as thebarcode, to eliminate the need for a separate Hyperlabel ink channel. AHyperlabel reader 101 can also be augmented to allow it to readconventional barcodes.

An RFID tag or barcode can encode the same item identifier and digitalsignature(s) as an item-indicating Hyperlabel tag.

Rather than encoding an item identifier explicitly in an RFID tag 210,barcode 211 or Hyperlabel tag 202, a random pattern can be printed andcharacterised to serve both as an item identifier and as a digitalsignature. The random pattern, or at least a portion thereof, serves asa “fingerprint” for the object.

In US Patent Application No. 20050045055 (“Security Printing Method”filed 28 Aug. 2003), the contents of which is incorporated herein byreference, Gelbart discusses the addition of powder taggants duringprinting for the purpose of subsequent authentication. As discussedelsewhere, both the presence of such a taggant and the exact randompattern formed by the taggant can be used as the basis forauthentication and possibly identification.

When the random pattern formed by the taggant is used as the basis forauthentication, the pattern is measured and recorded during productmanufacture or packaging, and is measured and verified, with referenceto the earlier recording, during subsequent authentication. The randompattern may cover the entire product surface or a subset thereof. Therecorded reference data (reference fingerprints) derived from thepattern may cover the entire pattern or a subset thereof. Theverification data (or fingerprint data) derived from the pattern duringauthentication typically relates to only a small area (e.g. onefingerprint) of the pattern. It is therefore necessary to know whicharea of the pattern is being verified, so that the verification data canbe compared with the correct subset of the reference data. In somesystems this relies on detecting other surface features, such as text orline art, and using such features as fiducials. Since such features aretypically not unique, this approach may require guidance from a humanoperator.

Hyperlabel tags 202, since they encode a two-dimensional coordinategrid, provide a unique set of fiducials against which both referencedata and verification data can be registered. This increases thereliability of authentication, and eliminates the need for humanguidance. The taggant may be mixed with either the infrared ink used toprint the Hyperlabels, or it may be mixed with the colored inks used toprint graphical user information. In FIG. 24, the ink used to print theword ‘TEA’ contains a randomly dispersed taggant. Alternatively, if thetaggant is applied by mixing it with an infrared ink, then the highdensity and (typical) full coverage of the Hyperlabel tag pattern 4ensures that the taggant is also densely present on the entire taggedsurface.

Although the random pattern formed by the taggant can be measured acrossthe entire tagged surface, at a minimum it can be measured within adefined region. This region can be graphically delineated to indicate toa user that this is where item-level identification and/orauthentication is available.

The random pattern can be characterised for each product package as itpasses through the packaging line, either while the packaging is stillon the web or sheet, or after the individual package is folded orfilled. At this stage the spatial nature of the random pattern isanalysed and recorded, either as a set of spatial features or as a hashof such spatial features. For example, each detected feature in therandom pattern can be assigned a quantised two-dimensional coordinatewithin the Hyperlabel coordinate system, and the set of quantisedcoordinates can be hashed to produce a single compact number.Verification then consists of generating the equivalent hash andcomparing it with the reference hash.

A Hyperlabel reader 101 may incorporate a reader for reading the randompattern formed by the taggant. If the taggant is read optically, thenthe Hyperlabel reader's image sensor can be used to read the taggantpattern. If the taggant uses a different wavelength to the Hyperlabeltag pattern, then the Hyperlabel reader 101 can alternate betweenactivating LEDs matched to the wavelength of the Hyperlabel tag pattern,and LEDs matched to the wavelength of the taggant. If the taggant needsto be imaged with a greater magnification than the Hyperlabel tagpattern, then the Hyperlabel reader can either always image at thegreater magnification, and subsample when processing Hyperlabel tagimages, or it can incorporate dual optical paths, optionally using abeam splitter to allow a single external aperture.

If no explicit item-level identifier is available (e.g. from an RFID tag210, barcode 211 or Hyperlabel tag 202), then the reference data (e.g.hash) can also serve as an item identifier. The product item is assigneda standard item identifier at time of manufacture, the standard itemidentifier is stored in the product database keyed by the referencedata, and the standard item identifier can subsequently be recoveredusing the verification data (e.g. hash) as a key to look up thedatabase, either for identification or verification purposes.

In the presence of layout-indicating Hyperlabel tags which encode aproduct identifier, the random pattern only needs to map to a serialnumber, not an entire item identifier.

A serialised product item carries a unique item identifier whichtypically consists of a product identifier and a serial number. The itemID may be carried by the product item in a number of ways. For example,it may be carried in a linear or two-dimensional barcode 211, a RFID tag210, or a Hyperlabel tag pattern 4. The product item may also carry adigital signature associated with the item ID which allows a reader toverify with a certain degree of certainty that the item is authentic.

It will be appreciated that any of the Hyperlabel tags 202 describedabove may be printed with inks according to the present invention.

The invention will now be described with reference to the followingexamples. However, it will of course be appreciated that this inventionmay be embodied in many other forms without departing from the scope ofthe invention, as defined in the accompanying claims.

EXAMPLES

In our earlier U.S. Pat. No. 7,148,345 and U.S. Patent Application No.60/851,754, filed on Oct. 16, 2006, the contents of which are hereinincorporated by reference, we described the preparation of various saltsof gallium naphthalocyanine tetrasulfonic acid. The skilled person willreadily appreciate that the ammonium salts of the present invention maybe easily prepared from corresponding sulfonic acids by conventionalmethods.

Preparative Example 1 Preparation of HydroxygalliumNaphthalocyaninetetrasulfonic Acid 4

(i) Gallium(III) chloride (5.70 g; 0.032 mol) was dissolved in anhydroustoluene (68 mL) under a slow stream of nitrogen and then the resultingsolution was cooled in ice/water. Sodium methoxide (25% in methanol;23.4 mL) was added slowly with stirring causing a thick whiteprecipitate to form. Upon completion of the addition, the mixture wasstirred at room temperature for 1 h and thennaphthalene-2,3-dicarbonitrile (22.8 g; 0.128 mol) was addedportionwise, followed by triethylene glycol monomethyl ether (65 mL).The thick slurry was distilled for 2 h to remove the methanol andtoluene. Once the toluene had distilled off, the reaction mixture becamehomogeneous and less viscous and stirred readily. Heating was continuedfor 3 h at 190° C. (internal). The brown/black reaction mixture wascooled to 60° C., diluted with chloroform (150 mL), and filtered undergravity through a sintered glass funnel. The solid residue was washedwith more chloroform (50 mL) and then a further portion (50 mL) withsuction under reduced pressure. The resulting dark green solid was thensequentially washed under reduced pressure with acetone (2×50 mL), DMF(2×50 mL), water (2×50 mL), acetone (2×50 mL), and diethyl ether (2×50mL). The moist solid was air-dried to a dry powder and then heated underhigh vacuum at ca. 100° C. for 1 h to complete the drying process.Naphthalocyaninatogallium methoxytriethyleneoxide 3 was obtained as afine dark green powder (23.14 g; 80%), λ_(max) (NMP) 770 nm.

(ii) Naphthalocyaninatogallium methoxytriethyleneoxide 3 (9.38 g; 0.010mol) was treated with 30% oleum (47 mL) by slow addition via a droppingfunnel while cooling in an ice/water bath under a nitrogen atmosphere.Upon completion of the addition, the reaction mixture was transferred toa preheated water bath at 55° C. and stirred at this temperature for 2 hduring which time the mixture became a homogeneous viscous dark bluesolution. The stirred reaction mixture was cooled in an ice/water bathand then 2-propanol (40 mL) was added slowly via a dropping funnel. Thismixture was then poured into 2-propanol (100 mL) using more 2-propanol(160 mL) to wash out the residues from the reaction flask. Diethyl ether(100 mL) was then added to the mixture which was then transferred to asintered glass funnel and filtered under gravity affording a moist darkbrown solid and a yellow/brown filtrate. The solid was washedsequentially with ether (50 mL), acetone/ether (1:1, 100 mL), and ether(100 mL) with suction under reduced pressure. The resulting solid (13.4g) after drying under high vacuum was then stirred in ethanol/ether(1:3, 100 mL) for 3 days and then filtered and dried to give thetetrasulfonic acid 4 as a fine red/brown solid (12.2 g; 105% oftheoretical yield; 90% purity according to potentiometric titration). ¹HNMR (d₆-DMSO) δ 7.97, 8.00 (4H, dd, J_(7,8)=J_(7,6)=7.2 Hz, H7); 8.49(4H, dd, J_(8,7)=7.2, J_(8,1)=5.7 Hz, H8); 8.84, 8.98 (4H, d,J_(6,7)=7.2 Hz, H6); 10.10, 10.19, 10.25 (4H, d, J_(1,8)=5.7 Hz, H1);11.13, 11.16 (4H, s, H4).

Example 1

To a solution of hydroxygallium(III) naphthalocyaninetetrasulfonic acid4 (10.2 g, 9.11 mmol) in methanol (250 mL) was added a solution ofAliquat® 336 (14.5 g, 0.036 mol) in methanol (50 mL). The solution wasconcentrated to half volume. The concentrated solution was diluted withwater (200 mL) to precipitate the product which was filtered off andwashed with warm acetone/water (50:50, 2×300 mL) and warm water (2×300mL), and air dried. The solid was then washed with boilingacetone/hexane (1:9, 2×300 mL) and dried to give the predominant product5 as a dark green powder (12.9 g, 56%).

¹H NMR (d₆-DMSO): δ 0.87 (36H, m); 1.25 (120H, m); 1.60 (24H, m); 2.96(12H, s); 3.20 (24H, m); 7.9-11.1 (20H, m).

Aliquat® 336 is a mixture of trioctylmethyl- and tridecylmethyl-ammoniumsalts. Example 1 was repeatable using isomerically puretrioctylmethylammonium bromide.

Example 2

Method A

A mixture of hydroxygallium(III) naphthalocyaninetetrasulfonic acid 4(849 mg, 0.758 mmol) and didodecyldimethylammonium bromide (1.61 g, 3.49mmol) in water (100 mL) was stirred for 5 min. The reaction mixture wasdiluted with water (100 mL) and extracted with chloroform/methanol(50:50, 2×200 mL). The combined organic layers were evaporated and theresidue was suspended in warm water (200 mL), filtered, and washed withwarm water and cold water/acetone (50:50) and dried to give the product6 as a dark-green powder (777 mg, 39%).

Method B

A mixture of tetrakis(tributylammonium) hydroxygallium(III)naphthalocyaninetetrasulfonate (5.74 g, 3.08 mmol) anddidodecyldimethylammonium bromide (5.71 g, 0.012 mol) in methanol (200mL) was evaporated to half volume with heating under a stream ofnitrogen and diluted with water (100 mL). The solid was filtered off andwashed with hot water (3×250 mL) and hot acetone/water (50:50, 3×250 mL)and allowed to dry. The solid was then washed further with toluene(2×250 mL) and boiling hexane (250 mL) and dried to give the product asa green powder (7.32 g, 90%).

¹H NMR (d₆-DMSO) δ 0.86 (24H, t, J=6.6 Hz); 1.25 (144H, m); 1.62 (16H,m); 3.20 (16H, m); 4.25 (24H, s); 7.9-11.1 (20H, m).

¹H NMR (d₆-DMSO): δ −0.46 (1H, s); 0.83 (24H, t, J=6.6 Hz); 1.25 (144H,m); 1.60 (16H, m); 3.20 (16H, m); 4.25 (24H, s); 7.9-11.1 (20H, m).UV-Vis-NIR (DMSO): λ_(max) 790, 704, 342 nm.

Example 3

A mixture of hydroxygallium(III) naphthalocyaninetetrasulfonic acid(2.15 g, 1.92 mmol) and cetylpyridinium chloride (4.22 g, 0.012 mol) inwater (20 mL) and methanol (100 mL) was evaporated to dryness withheating and stirring under a stream of nitrogen. The solid was suspendedin acetone (200 mL), and filtered off. It was washed with water (2×200mL), acetone (2×200 mL) and cold methanol (1×200 mL), and dried to givethe product as a dark-green powder (3.09 g, 67%).

¹H NMR (d₆-DMSO) δ 0.85 (12H, t, J=6.6 Hz); 1.20 (104H, m); 1.89 (8H,m); 4.58 (8H, t, J=7.5 Hz); 7.9-11.1 (40H, m).

UV-Vis-NIR (DMSO): λ_(max) 791, 705, 342 nm.

Example 4

A mixture of hydroxygallium(III) naphthalocyaninetetrasulfonic acid (643mg, 0.575 mmol) and cetyltrimethylammonium bromide (839 mg, 2.30 mmol)in chloroform (50 mL) was heated at reflux for 1 h. Water (50 mL) wasadded and stirring was continued for 15 min. The reaction mixture wasdiluted with chloroform (200 mL) and washed with water (200 mL). Theorganic layer was evaporated to dryness and the residue was suspended inwater (200 mL) and filtered off. The product 8 was washed with hot waterand cold acetone, and dried to give a dark-green powder (448 mg, 35%).

¹H NMR (d₆-DMSO): δ 0.84 (12H, t, J=6.6 Hz); 1.20 (104H, m); 1.63 (8H,m); 1.89 (12H, s); 3.10 (36H, s); 3.20 (8H, m); 8.0-11.2 (20H, m).

UV-Vis-NIR (DMSO): λ_(max) 787, 711, 338 nm.

Example 5 Tetrakis(tetraoctylammonium) Salt

A mixture of hydroxygallium(III) naphthalocyaninetetrasulfonic acid(1.67 g, 1.49 mmol) and tetraoctylammonium bromide (3.32 g, 6.08 mmol)in water (5 mL) and methanol (80 mL) was evaporated to dryness withheating and stirring under a stream of nitrogen. The solid was suspendedin hot water (200 mL), filtered, washed with hot water (2×200 mL), andallowed to dry. The solid was then washed with diethyl ether (1×200 mL),acetone/hexane (1:9, 2×200 mL) and hexane (1×200 mL) and dried to givethe product as a dark-green powder (1.34 g, 30%).

¹H NMR (d₆-DMSO) δ 0.87 (48H, t, J=7.0 Hz); 1.27 (160H, m); 1.56 (32H,m); 3.16 (32H, m); 7.9-11.2 (20H, m).

Example 6 Tetrakis(tetraoctadecylammonium) Salt

A mixture of hydroxygallium(III) naphthalocyaninetetrasulfonic acid(1.62 g, 1.44 mmol) and tetraoctadecylammonium bromide (5.00 g, 4.51mmol, 3.1 equiv.) in water (5 mL), methanol (100 mL) and dichloromethane(20 mL) was evaporated to dryness with heating and stirring under astream of nitrogen. The solid was suspended in hot methanol (200 mL) andfiltered, washed with acetone (2×200 mL), and allowed to dry. The solidwas then dissolved in chloroform/hexane (2:8, 500 mL) and filtered, andthe solvents were removed. The solid was suspended in hot acetone (300mL) and filtered, washed with cold hexane (1×200 mL) and dried to givethe product as a green powder (2.26 g, 43%).

¹H NMR (CDCl₃) δ 0.8-3.8 (592H, m); 7.0-11.0 (20H, m).

Example 7 Tetrabenzethonium Salt

To a solution of hydroxygallium(III) naphthalocyaninetetrasulfonic acid(1.78 g, 1.59 mmol) in water (20 mL) and methanol (100 mL) was added asolution ofbenzyldimethyl-p-(1,1,3,3-tetramethylbutyl)phenoxyethoxyethylammoniumchloride (Benzethonium chloride) (3.25 g, 7.25 mmol) in methanol (20mL). The reaction mixture was evaporated to half volume with heatingunder a stream of nitrogen and diluted with water (100 mL). The solidwas filtered off and washed with hot water (3×250 mL) and allowed todry. The solid was then washed with diethyl ether (2×200 mL) and boilinghexane (1×200 mL) and dried to give the product as a green powder (2.78g, 63%).

¹H NMR (d₆-DMSO) δ 0.66 (36H, s); 1.27 (24H, s); 1.67 (8H, s); 3.04(24H, s); 3.18 (8H, d, J=5.4 Hz); 3.5-4.1 (32H, m); 4.61 (8H, s); 6.82(8H, d, J=8.7 Hz); 7.25 (8H, d, J=8.7 Hz); 7.4-7.6 (20H, m); 7.9-11.2(20H, m).

Example 8 Tetrakis(trioctadecylmethylammonium) Salt

To a solution of hydroxygallium(III) naphthalocyaninetetrasulfonic acid(1.26 g, 1.13 mmol) in water (20 mL) and acetone (100 mL) was added asolution of trioctadecylmethylammonium bromide (3.21 g, 3.69 mmol) inacetone (20 mL) and chloroform (50 mL). The reaction mixture wasevaporated to half volume with heating under a stream of nitrogen andthe solid was filtered off and washed with hot acetone (3×300 mL), hotdimethyl sulfoxide (100 mL) and hot acetone (2×200 mL), and dried togive the product as a green powder (3.27 g, 83%).

¹H NMR (d₆-DMSO/CDCl₃): δ 0.82 (36H, m); 1.19 (360H, m); 1.60 (24H, m);2.7-3.5 (36H, m); 7.9-11.2 (20H, m).

Example 9 Tetrakis(tetrahexylamine) Salt

To a solution of hydroxygallium(III) naphthalocyaninetetrasulfonic acidtetra sodium salt (2.51 g, 2.20 mmol) in water (10 mL) and methanol (100mL) was added a solution of tetrahexylammonium bromide (4.32 g, 9.94mmol) in methanol (30 mL). The reaction mixture was evaporated to halfvolume with heating under a stream of nitrogen, and diluted with water(100 mL). This caused the product and excess tetrahexylammonium bromideto oil out. The supernatant liquid was decanted off and the oil wassuccessively washed with acetone/water (50:50, 200 mL) until the oilbegan to solidify. The solid was suspended in warm acetone/water (50:50,200 mL), filtered off, washed with hot water (3×200 mL) and dried. Thesolid was washed with hexane (1×200 mL) and dried to give the product asa dark-green powder (903 mg, 16%).

¹H NMR (d₆-DMSO) δ 0.88 (48H, m); 1.1-1.7 (128H, m); 3.16 (32H, m);7.9-11.2 (20H, m).

Example 10 Tetrakis(trioctylamine) Salt

To a solution of hydroxygallium(III) naphthalocyaninetetrasulfonic acid(1.47 g, 1.31 mmol) in water (20 mL) and methanol (100 mL) was addedtrioctylamine (2.3 mL, 1.85 g, 5.24 mmol). The product immediatelyprecipitated and was filtered off, washed with hot water (2×300 mL) andhot methanol/water (70:30, 200 mL) and dried. The solid was then washedwith boiling hexane (200 mL) and dried to give the product as a greenpowder (1.74 g, 52%).

¹H NMR (CDCl₃): δ 0.86 (36H, t, J=7.2 Hz); 1.26 (120H, m); 1.57 (24H,m); 3.02 (24H, m); 7.9-11.2 (20H, m).

Example 11 Tetrakis(tridodecylamine) Salt

To a solution of hydroxygallium(III) naphthalocyaninetetrasulfonic acid(1.69 g, 1.51 mmol) in water (20 mL) and methanol (100 mL) was addedtridodecylamine (4 mL, 3.28 g, 6.28 mmol). The product and excess amineimmediately oiled out of solution and the aqueous supernatant liquid wasdecanted off. The oil was dissolved in hexane (400 mL) and washed withaqueous acetic acid (0.1 M, 400 mL). The organic layer was dried(Na₂SO₄) and the solvent was removed. The product was suspended indimethyl sulfoxide (300 mL), filtered, washed with dimethyl sulfoxide(200 mL), methanol (2×200 mL) and water (2×200 mL) and dried to give theproduct as a dark-green powder (1.56 g, 32%).

¹H NMR (CDCl₃) δ 0.7-3.3 (300H, m); 7.9-11.2 (20H, m).

Comparative Example 1

To a solution of hydroxy gallium(III) naphthalocyaninetetrasulfonic acid4 (29.1 g, 0.026 mol) in water (50 mL) and methanol (350 mL) was added asolution of trihexyltetradecylphosphonium chloride (50.0 g, 0.096 mol)in methanol (50 mL). The solution was concentrated to half volume andthe concentrated solution was diluted with water (100 mL) to precipitatethe product. The phosphonium salt was filtered off and washed with warmacetone/water (50:50, 2×300 mL) and warm water (2×300 mL) and air dried.The solid was then washed with boiling hexane (2×300 mL) and dried togive the product 9 as a dark green powder (63.1 g, 86%).

¹H NMR (d₆-DMSO): δ 0.85 (48H, m); 1.0-1.5 (192H, m); 1.90 (32H, m);7.9-11.1 (20H, m).

UV-Vis-NIR (DMSO): λ_(max) 795 nm (ε=365,000); 756 nm (ε=59,000); 706 nm(ε=65,000); 341 nm (ε=102,000).

UV-Vis-NIR (CHCl₃): λ_(max) 790 nm (ε=87,000); 333 nm (ε=85,000).

Comparative Example 2

To a solution of gallium(III) chloride (3.68 g, 0.0206 mol) in anhydroustoluene (30 mL) was added dropwise a solution of sodium methoxide inmethanol (25%, 14.5 mL=3.63 g, 0.067 mol) to give a colourlessprecipitate. 2,3-Naphthalenedinitrile (14.6 g, 0.0820 mol, 3.98 eq.),1-hexadecanol (26.8 g, 0.11 mol) and 1,2-dichlorobenzene (75 mL) wereadded and the reaction mixture was heated in order to distill off themethanol and toluene. The internal temperature was raised to 170° C. andheating was continued overnight. The temperature was increased todistill about 20 mL of the dichlorobenzene. The reaction mixture wascooled, diluted with acetone (100 mL) and the product was collected byfiltration. The solid was washed with acetone, water, and acetone, andair-dried to give the product 10 as a dark-green powder (17.85 g, 85%).

¹H NMR (d₆-DMSO): δ 0.86 (3H, m); 1.15-1.25 (29H, m); 8.05 (8H, m); 8.85(8H, m); 10.15 (8H, m).

UV-Vis-NIR (NMP, 5.176×10⁻⁶ M): λ_(max) 770 nm (ε=277,000); 690 nm(ε=51,000); 338 nm (ε=95,000).

Comparative Example 3 Gallamine Salt

To a solution of hydroxygallium(III) naphthalocyaninetetrasulfonic acid(2.17 g, 1.94 mmol) in water (20 mL) and methanol (100 mL) was added asolution of 1,2,3-tris(2-diethylaminoethoxy)benzene triethiodide(gallamine triiodide) (3.66 g, 4.10 mmol) in methanol (20 mL). Thereaction mixture was evaporated to dryness with heating and stirringunder a stream of nitrogen. The residue was suspended in acetone (200mL), filtered, washed with acetone (2×200 mL) and methanol (1×200 mL)and dried to give the product as a dark-green powder (3.26 g, 70%).

¹H NMR (d₆-DMSO) δ 1.22 (54H, m); 3.5-4.5 (48H, m); 6.86 (4H, d, J=8.1Hz); 7.09 (2H, t, J=8.1 Hz); 7.9-11.2 (20H, m).

This compound was unable to be formulated as described below and so noreflectance spectrum was recorded.

Comparative Example 4 Paraquat Salt

To a solution of hydroxygallium(III) naphthalocyaninetetrasulfonic acid(2.37 g, 2.12 mmol) in water (20 mL) and methanol (100 mL) was added asolution of 1,1′-dimethyl-4,4′-bipyridinium dichloride hydrate(Paraquat) (325 mg, 1.26 mmol) in water (5 mL). The reaction mixture wasevaporated to dryness with heating and stirring under a stream ofnitrogen. The residue was suspended in acetone (200 mL), filtered,washed with acetone (2×200 mL), cold methanol (1×200 mL) and t-butylmethyl ether (1×200 mL), and dried to give the product as a dark-greenpowder (1.91 g, 61%).

¹H NMR (d₆-DMSO) δ 1.12 (12H, s); 7.9-11.2 (36H, m).

This compound was unable to be formulated as described below and so noreflectance spectrum was recorded.

Comparative Example 5 Tetrakis(trimethylphenylammonium) Salt

To a solution of hydroxygallium(III) naphthalocyaninetetrasulfonic acid(1.65 g, 1.48 mmol) in water (20 mL) and methanol (100 mL) was added asolution of trimethylphenylammonium chloride (1.23 g, 7.16 mmol) inmethanol (20 mL). The reaction mixture was evaporated to dryness withheating under a stream of nitrogen. The solid was suspended in acetone(200 mL), filtered, washed with acetone (200 mL) and tert-butyl methylether (200 mL), and dried to give the product as a dark-green powder(1.54 g, 63%).

¹H NMR (d₆-DMSO) δ 3.67 (36H, s); 7.5-11.2 (40H, m).

Reflectance Spectra

The hydrophobic salts prepared in the Examples weredissolved/homogenized in Syntholit P101 (70% in Shellsol A, SynthopolChemie) and xylenes (1:4 ratio) at 2% w/v. These formulations were thenapplied with a draw-down rod to Geographics photographic paper (glossy,130 gsm). Spectra were recorded on a Cary 50 spectrophotometer inreflectance mode.

In general, those compounds that dispersed to give 70-80% absorption atλ_(max) were deemed effective while compounds that gave weak absorptionat λ_(max) were deemed to be poorly dispersible.

Evaluation of Phthalocyanine Salts as Offset Candidates

Table 1 below gives a qualitative classification of the phthalocyaninesalts described above according to quality of spectra.

TABLE 1 A B C 5 8 13 7 12 14 6 20 16 11 21 17 15 18 19Three broad groups of compounds were able to be discerned:

-   A—dispersed easily, sharp Q band with increased monomer component-   B—dispersed easily, broad Q band-   C—failed to disperse readily and/or poor spectrum

Of the candidates tested those that gave optimum spectra with a highdegree of monomeric component are the tetrakis(tetraoctylammonium) salt6, the tetrakis(trioctadecylmethylammonium) salt 14, and thetetrakis(tetrahexylammonium) salt 15.

The best candidates for use as offset pigments tended to have at leastone or at least two long flexible alkyl chains (>C6) attached to aquaternary nitrogen. Very long flexible chains e.g. tetra-C18 or longalkyl chains attached to a tertiary nitrogen tended to give rise tobroader Q-bands. It is recognized that this variation may well bevehicle dependent and, therefore, it is expected that candidates ingroups A or B are potentially useful and fine tuning could be achievedthrough formulation.

Salts with compact counterions with rigid hydrophobic regions are notreadily dispersible in offset vehicles.

Absorption Characteristics

As can be seen from FIGS. 25 and 27, the Aliquat® 336 salt 5 has strongabsorption in the near-IR region and low absorption in the visibleregion. Anecdotal observations by the naked eye show that the Aliquat®336 salt 5 is only slightly visible when printed at 1%, 2% and 3% w/wdye loadings.

FIG. 28 shows that at 3% w/w dye loading, the Aliquat® salt 5 isapproaching saturation in terms of NIR absorption, and by going to 2%w/w dye loading the performance is only marginally compromised.

Comparing FIGS. 27 and 30, it can be seen that, at 3% w/w dye loading,the Aliquat® 336 salt 5 has much lower absorption in the visible regionthan the unsulfonated gallium naphthalocyanine 10. As foreshadowedabove, the low visible absorption of ammonium salts according to thepresent invention is understood to be due to the ammonium cationinterrupting aggregation of the dye molecules.

In general, the ammonium salt 5 has similar absorption characteristicsto the phosphonium salts described in our earlier application No.60/851,754 filed on Oct. 16, 2006).

Stability Testing

The Aliquat 336 salt 5 was dissolved at 3% w/w in a commerciallyavailable offset ink vehicle, Matrix ECO PMS Trans White (DIC ColortronPty Ltd, catalogue number MX 6010/1). Continuous exposure of printedswatches to direct sunlight and office atmospheric pollutants wasmonitored over a period of 5 months. The behaviour of the Aliquat 336salt 5 and the phosphonium salt 9 was compared (Table 2).

TABLE 2 Sample % decrease in absorbance after 5 months 5 3% w/w(sample 1) 10 5 3% w/w (sample 2) 13 9 3% w/w 21

From Table 1 it can be seen that the ammonium salts 5 exhibit improvedstability at 3% w/w dye-loading compared to the correspondingphosphonium salt 9.

It has therefore been demonstrated that the ammonium salts according tothe present invention are excellent candidates for offset dyes. Theyhave surprisingly high stability when printed. Furthermore, the IR dyeshave low visibility compared to unsulfonated dyes.

1. A phthalocyanine salt comprising one or more sulfonate groups,wherein a counterion of at least one sulfonate group is an ammoniumcation comprising at least 20 carbon atoms.
 2. The phthalocyanine saltof claim 1, wherein said ammonium cation comprises at least one groupC₆₋₃₀ alkyl group or at least one C₆₋₃₀ benzylalkyl group.
 3. Thephthalocyanine salt of claim 1 comprising a plurality of sulfonategroups.
 4. The phthalocyanine salt of claim 1, which is an IR-absorbingphthalocyanine salt.
 5. The phthalocyanine salt of claim 1, which is anaphthalocyanine.
 6. The phthalocyanine salt of claim 1, wherein saidammonium cation is of formula: N⁺(R^(m))(R^(n))(R^(s))(R^(t)), wherein:each of R^(m), R^(n), R^(s) and R^(t) is independently selected from thegroup consisting of: C₁₋₃₀ alkyl, C₅₋₁₂ aryl and C₅₋₃₀ arylalkyl; orR^(m) and R^(n) are together joined to form a C₅₋₁₀ heterocycloalkylgroup, with R^(s) and R^(t) being independently selected from the groupconsisting of: C₁₋₃₀ alkyl, C₅₋₁₂ aryl and C₅₋₃₀ arylalkyl; or R^(m),R^(n) and R^(s) are together joined to form a C₅₋₁₀ heteroaryl group,with R^(t) being independently selected from the group consisting of:C₁₋₃₀ alkyl, C₅₋₁₂ aryl and C₅₋₃₀ arylalkyl.
 7. The phthalocyanine saltof claim 6, wherein at least one of R^(m), R^(n), R^(s) and R^(t)comprises 10 or more carbon atoms.
 8. The phthalocyanine salt of claim6, wherein at least two of R^(m), R^(n), R^(s) and R^(t) comprise 6 ormore carbon atoms.
 9. The phthalocyanine salt of claim 6, wherein atleast three of R^(m), R^(n), R^(s) and R^(t) comprise 6 or more carbonatoms.
 10. The phthalocyanine salt of claim 6, wherein each of R^(m),R^(n), R^(s) and R^(t) is independently selected from C₁₋₃₀ alkyl. 11.The phthalocyanine salt of claim 6, wherein said ammonium cation is offormula:


12. The phthalocyanine salt of claim 1, wherein said salt is of formula(Ia):

wherein: Q¹, Q², Q³ and Q⁴ are the same or different and areindependently selected from the group consisting of: a C₃₋₂₀ arylenegroup or a C₃₋₂₀ heteroarylene group; M is (H₂) or a metal selected fromthe group consisting of: Si(A¹)(A²), Ge(A¹)(A²), Ga(A¹), Mg, Al(A¹),TiO, Ti(A¹)(A²), ZrO, Zr(A¹)(A²), VO, V(A¹)(A²), Mn, Mn(A¹), Fe, Fe(A¹),Co, Ni, Cu, Zn, Sn, Sn(A¹)(A²), Pb, Pb(A¹)(A²), Pd and Pt; A¹ and A² areaxial ligands, which may be the same or different, and are selected fromthe group consisting of: —OH, halogen, —OR³, —OC(O)R⁴ and—O(CH₂CH₂O)_(e)R^(e) wherein e is an integer from 2 to 10 and R^(e) isH, C₁₋₈ alkyl and C(O)C₁₋₈ alkyl; R³ is selected from the groupconsisting of: C₁₋₂₀ alkyl, C₅₋₁₂ aryl, C₅₋₂₀ arylalkyl andSi(R^(x))(R^(y))(R^(z)); R⁴ is selected from the group consisting of:C₁₋₂₀ alkyl, C₅₋₁₂ aryl and C₅₋₂₀ arylalkyl; R^(x), R^(y) and R^(z) arethe same or different and are selected from the group consisting of:C₁₋₁₂ alkyl, C₅₋₁₂ aryl, C₅₋₁₂ arylalkyl, C₁₋₁₂ alkoxy, C₅₋₁₂ aryloxyand C₅₋₁₂ arylalkoxy; and Z₁ ⁺, Z₂ ⁺, Z₃ ⁺ and Z₄ ⁺ may be the same ordifferent and are each an ammonium cation comprising at least 20 carbonatoms.
 13. The phthalocyanine salt of claim 1, which is of formula (I):

wherein M is Ga(A¹); A¹ is an axial ligand selected from the groupconsisting of: —OH, halogen, —OR³, —OC(O)R⁴ and —O(CH₂CH₂O)_(e)R^(e)wherein e is an integer from 2 to 10 and R^(e) is H, C₁₋₈ alkyl orC(O)C₁₋₈ alkyl; R³ is selected from the group consisting of: C₁₋₂₀alkyl, C₅₋₁₂ aryl, C₅₋₂₀ arylalkyl and Si(R^(x))(R^(y))(R^(z)); R⁴ isselected from the group consisting of: C₁₋₂₀ alkyl, C₅₋₁₂ aryl orC_(5-20 arylalkyl;) R^(x), R^(y) and R^(z) may be the same or differentand are selected from the group consisting of: C₁₋₁₂ alkyl, C₅₋₁₂ aryl,C₅₋₁₂ arylalkyl, C₁₋₁₂ alkoxy, C₅₋₁₂ aryloxy and C₅₋₁₂ arylalkoxy; andZ₁ ⁺, Z₂ ⁺, Z₃ ⁺ and Z₄ ⁺ may be the same or different and are each anammonium cation comprising at least 20 carbon atoms.
 14. A solvent-basedor oil-based ink comprising a phthalocyanine salt according to claim 1.15. An analog printer, or a module thereof, comprising an ink supply, aprinting plate and means for disposing ink from said ink supply ontosaid plate, wherein said ink comprises a phthalocyanine salt accordingto claim
 1. 16. A substrate having a phthalocyanine salt according toclaim 1 disposed thereon or therein.
 17. The substrate of claim 1, whichis a label, packaging or surface of a product item.
 18. A system forinteracting with a coded substrate, said system comprising: a substratehaving human-readable information and machine-readable coded datadisposed thereon or therein; and a sensing device for reading themachine-readable coded data, wherein said coded data comprises aphthalocyanine salt according to claim 1.